No low beams. High beams only. [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: No low beams. High beams only.


loriegood
08-04-2009, 12:11 PM
Hello. I'm new on this website and I'm hoping to find an answer to my problem. This weekend my low beams just stopped working. My high beams are fine. If I leave the high beams on the lights will come on automatically like they are supposed to, but only the brights.

Also, for a couple of weeks there is a ticking noise come from the front of the car. It starts at idle and lasts for less than a minute and then stops.

If anyone has an answer I would appreciate it. I'm hoping it won't be expensive to fix.

Thanks for this forum. I've already seen some very interesting information here.
:grouphug:

the roadie
08-04-2009, 01:35 PM
Low beams have a fuse for each side and a shared relay. Get into the front fuse block, and interchange black relays 45 and 46. If you have a bad relay 46 for the low beams, the electric fan clutch may quit working for a bit, but that won't hurt anything for a few minutes.

The ticking is likely the fan clutch. Remove relay 45 altogether for a few minutes on a cold start and see if the noise goes away. The fan clutches (run a search and read for a half hour or so) are a very, very high failure rate item, especially previous to a redesign in 2005. If you're not overheating, then it's still working OK, but you might want to save up or anticipate it dying in a year. How fast is the ticking? Once a second? Your vehicle may also benefit from a dealer reflash of the computer that addresses this issue and also low AC cooling at initial start-up. Some dealers charge a fair price for this and others use it to send their kids though dental school.

rbarrios
08-04-2009, 06:56 PM
welcome loriegood...
The roadie is right on..... try what he says.

loriegood
08-16-2009, 04:57 PM
Thanks, the relay was the fix for the headlights. Now I'm trying to find one for a reasonable price... Any ideas? GM Parts direct want 25 plus s/h...

As for the fan clutch, it ticks about once a second... but not constantly...

Must start saving...

Thanks for your help!!

P.S. Is there an after market replacement for the headlight relay? I'm having trouble finding one at Kragen, Napa, etc...

RayVoy
08-16-2009, 10:30 PM
They should be a common after market part.
I bought one years ago (different GM truck), don't remember where, sorry.

the roadie
08-16-2009, 10:55 PM
Its aftermarket replacement is an Airtex 1R1944, but for some dumb reason some parts store's software doesn't seem to know it. And other ones just don't stock it. Sigh...

Oh, and it isn't cheap anywhere. $25 is a good deal. Usually it's $28-38. Dealers can attempt to charge over $50 for it. It's "special".

You might try asking for the Chevy SSR low beam relay. Same idiot GM design team worked on that puppy.

stretch
08-17-2009, 01:56 AM
I've been scanning websites to find an answer to why the low beams in my 03 Trailblazer LT just quit working when the fuse and bulbs were fine. It ended up being the relay. Thanks!! Lots of great info on this website! p.s. Thanks Roadie for the graphics. That made it a 2 minute job instead of a trip to the mechanic.

blazerboy04
08-17-2009, 02:10 AM
This happend to me I had no headlights and was freaking out checked all the fuses for the lights wasn't that. My friend came over we pulled a couple of fuses found out that is was a fuse for power seats.... well mine doesn't have them. It was blown i replaced it and tada headlights and high beams worked again. JUST CHECK EACH FUSE!! Could save alot of agrivation. I know it did for me. Hope it helps.

the roadie
08-17-2009, 03:01 PM
blazerboy - please let me know what the fuse location that you had a blown fuse in that was labeled for power seats, that really took out the headlights?

I think the only one labeled power seats is a circuit breaker, #8, under the rear seat. Headlights can be taken out by a problem with the BCM, which could be a rear fuse block issue, but it wouldn't be the power seat CB, more like fuses 4, 7, 32, 40, 50 or 52.

blazerboy04
08-17-2009, 07:54 PM
I wish i knew exactly which fuse it was. I was freaking out. I know the fuse was under the hood and it wasn't my headlight fuse. My friend John who is a mechanic came over. He said just start pulling fuses under the hood so we did. We started with the obvious the two low beam fuses and the two high beam fuses. They were fine. We began to pull others out and found a blown fuse It was for something totally useless lol just wish i could remember what it was for. Everything in the truck works and worked fine at the time. We replaced that fuse and the headlights worked again high and low. I'm sorry i couldn't be more usefull but I understand what is happening to you as it happend to me. Check everyone under the hood it will only take about 10 min and can pay off. Let me know if you find anything I would love to see if this is a repeat problem. Good Luck :D

GunSlinger09
08-19-2009, 12:04 PM
I havent posted here for a while and I had my low beams doing the same thing! I had the same problem with all the dealers pulling the wrong part I finally found it for 40 bucks at auto zone able to be there tomorrow.

Everywhere else it was around the same price and it would take 3-5 days.....I work nights so I need head lights.......sigh.... oh well

BLAZEN03
09-23-2009, 01:33 AM
Hey gunslinger do you have a pt# for that relay?

dac_daddy
10-12-2009, 10:18 PM
Thank you! Now my headlights work. Now time to find a replacement relay...

loriegood
10-13-2009, 12:43 AM
This forum has been so incredibly helpful to me! Thank you to the people who post solutions :woot: !!

Firehound
10-19-2009, 11:20 PM
yea! this thread was a big help!!

my relay chose to give out around sundown on day 2 of a 2 day road-trip... 2 hours from our destination. an hour worth of troubleshooting got us no-where, so I drove from Madison to Appleton, Wisconsin with my highbeams... p***ed off alota folks but got here safely...


I found not 1, but 2 relays from a wrecked 03 TB in a salvage yard... paid $5 for the pair, so now I have a spare...

Firehound
10-31-2009, 08:41 PM
I recently had the common issue of a failed Headlight Drive Module relay. I've managed to scrounge several spare relays while browsing the local junkyards for another part that I need. All of the junkyard operators sold me a pair for $2-5, and one guy even let me take them when I pulled out my credit card since I didnt have cash...

so.. What am I gonna do with these extra relays? I'm gonna keep a spare one or two for me, and the rest are for Trailvoy.com members. If you need one of these relays, send me a PM with your address and I'll send ya one as long as I have a supply.

Roll safely!!

fj4072
11-01-2009, 01:33 AM
Low beams have a fuse for each side and a shared relay. Get into the front fuse block, and interchange black relays 45 and 46. If you have a bad relay 46 for the low beams, the electric fan clutch may quit working for a bit, but that won't hurt anything for a few minutes.

The ticking is likely the fan clutch. Remove relay 45 altogether for a few minutes on a cold start and see if the noise goes away. The fan clutches (run a search and read for a half hour or so) are a very, very high failure rate item, especially previous to a redesign in 2005. If you're not overheating, then it's still working OK, but you might want to save up or anticipate it dying in a year. How fast is the ticking? Once a second? Your vehicle may also benefit from a dealer reflash of the computer that addresses this issue and also low AC cooling at initial start-up. Some dealers charge a fair price for this and others use it to send their kids though dental school.



I am now having my low beams go out intermittently then come back on after I get out and slam the door or something. Even went back on after I popped up the metal piece that hold the headlight in place. I've checked all my fuses, looks good, but for a problem that is intermittent, could this still be the relay? By the way, my high beams work everytime. I had to use my highbeams to get home from taking my daughter tricker or treating tonight, lots of upset people. 03 TB LS Any help would be appreciated.

Firehound
11-01-2009, 01:48 AM
sounds exactly like a relay starting to do bad...

my recommendation would be head down to your local salvage yard or pick-a-part and see if you can find one in a wreck. (i've found the fuse box in the back seat of several TB/Envoy hulks...)

or.. I still have 1 or 2 spares available, see my previous post...

fj4072
11-01-2009, 11:45 AM
sounds exactly like a relay starting to do bad...

my recommendation would be head down to your local salvage yard or pick-a-part and see if you can find one in a wreck. (i've found the fuse box in the back seat of several TB/Envoy hulks...)

or.. I still have 1 or 2 spares available, see my previous post...


OK will do, just checked out Autozones website, it's $14.99 here part # 19264, hope it the right one looks different from the one that Roadie pictured, or I'll try the wrecking yard. What years would be the same parts, I think it's 02-04 TB/Envoy? Thank you very much!

the roadie
11-01-2009, 12:53 PM
OK will do, just checked out Autozones website, it's $14.99 here part # 19264, hope it the right one looks different from the one that Roadie pictured,All years are the same for relays and such. Be VERY CAREFUL looking stuff up on the Autozone site. The right black covered relay for the LOW BEAMS is:

Duralast / Relay - Headlamp
20601
$39.99
http://contentinfo.autozone.com/znetcs/product-info/en/US/wl2/20601/image/5/

The Duralast 19264 you found is the gray one used in many other locations such as HIGH BEAM, but it's not the special solid state black one used for the low beam or fan clutch.

Gray:
http://contentinfo.autozone.com/znetcs/product-info/en/US/wl2/19264/image/5/

fj4072
11-01-2009, 01:07 PM
You da man, thank you again!!

glimpse22
11-10-2009, 04:22 PM
Thanks for all the info! My headlights faded off the other day.... Changed the fuses around and no more problems....Maybe I should start changing all the fuses since I have a 2003 LTZ?!?

the roadie
11-10-2009, 05:14 PM
.... Changed the fuses around and no more problems....Maybe I should start changing all the fuses since I have a 2003 LTZ?!?Good idea. One of the automotive industry's nasty little secrets. Fuses have a known failure mechanism and they get unreliable with age after 4-5 years. The 10 A are the worst variety for this syndrome. Definitely get a new set and swap them all out whenever you clean the throttle body. It's called AFS - aging fuse syndrome.

Also, make sure you don't get them from a store that doesn't rotate their stock. The time they sit on the shelf could use up half or more of their lifetime. It doesn't depend on their being powered up - it's a microcrystalline dendritic growth in the atoms of the fuse metal structure itself. Good call. :thumbsup:

fj4072
11-11-2009, 06:45 PM
All years are the same for relays and such. Be VERY CAREFUL looking stuff up on the Autozone site. The right black covered relay for the LOW BEAMS is:

Duralast / Relay - Headlamp
20601
$39.99
http://contentinfo.autozone.com/znetcs/product-info/en/US/wl2/20601/image/5/

The Duralast 19264 you found is the gray one used in many other locations such as HIGH BEAM, but it's not the special solid state black one used for the low beam or fan clutch.

Gray:
http://contentinfo.autozone.com/znetcs/product-info/en/US/wl2/19264/image/5/



Update: I took your advise and got a new relay. You were right about their website, they kept pulling up the incorrect part # while I was there in person, I gave them the # you gave me and ordered it. Before hand, I ran around to many different auto parts distributors, I took the relay out everytime and showed it to them. I waited 2 days for my new special order relay to come in, in those 2 days, my old relay started working again. Maybe me removing the relay so many times cleaned the contacts that the relay goes into? Maybe, but it's working now, and at least I'm sitting more comfortable knowing I have a brand new one as a back up. Thanks again!

harner
11-15-2009, 04:41 PM
Hello!

This is my first post on TrailVoy. I knew the site existed and lurked here before, but this thread made me join. My '06 TBSS low beams just stopped working last night while my girlfriend was driving it home.

At first I naturally thought she did something to turn them off. After I sat down and checked the fuses and bulbs and found no issues, I consulted the Internet. I switched relays 45 and 46 and found the problem.

So now my Q is that is it safe to leave the fan clutch relay out until I get the new relay in? I planned on getting one shipped NBD via RockAuto since I can't find any local and dealers are around the same price.

Thanks.

the roadie
11-15-2009, 04:55 PM
Glad you found the answer you needed. At highway speeds, the radiator cools enough by natural airflow, so the fan isn't needed. It's just in slow traffic in hot conditions you'll overheat without the fan running. Just watch your temp gauge for going over 210. If it does, get out of traffic and either drive on side streets or turn the engine off to cool off. PA in November is unlikely to be a risk, unless you get caught in some holiday traffic before you get your relay.

harner
11-15-2009, 05:27 PM
My fan is driven by the motor, it's not electric. So how would an electric clutch relay effect the fan that cools the motor?

For the record, thanks for your response. Luckily I got it on my cell while I was out and drove about 7-8 miles home after I switched the relays just to try it out. It didn't budge over 210.

Luckily I work about 20min from home and I can take back roads primarily to and from to avoid traffic.

:thx

WOOLUF1952
11-16-2009, 03:40 AM
My fan is driven by the motor, it's not electric. So how would an electric clutch relay effect the fan that cools the motor?

For the record, thanks for your response. Luckily I got it on my cell while I was out and drove about 7-8 miles home after I switched the relays just to try it out. It didn't budge over 210.

Luckily I work about 20min from home and I can take back roads primarily to and from to avoid traffic.

:thx
The engine drives the fan but, if the relay is out, the fan is free wheeling and only turns from the friction of the water pump. Not fast enough if you are in slow bumper to bumper traffic.

harner
11-16-2009, 09:06 AM
That is interesting. I'll give it a go today and see how it does.

Thanks, that is the answer I am looking for.

shecar
11-19-2009, 01:30 PM
We are having the same problem with the low headlights turning off all of a sudden on my dad's 04' TrailBlazer. The High Beams work fine. He swapped the relays as suggested and now the low headlights turn on when you turn them on but they do not work on the automatic setting. Also, the fan clutch mentioned is still working properly even when the relays were swapped which makes me believe the relay is ok. What should we try next?

fj4072
11-19-2009, 02:02 PM
Good idea. One of the automotive industry's nasty little secrets. Fuses have a known failure mechanism and they get unreliable with age after 4-5 years. The 10 A are the worst variety for this syndrome. Definitely get a new set and swap them all out whenever you clean the throttle body. It's called AFS - aging fuse syndrome.

Also, make sure you don't get them from a store that doesn't rotate their stock. The time they sit on the shelf could use up half or more of their lifetime. It doesn't depend on their being powered up - it's a microcrystalline dendritic growth in the atoms of the fuse metal structure itself. Good call. :thumbsup:


I agree good idea. I just changed all of mine out while also cleaning with contact cleaner. You're right those 10A fuses were definitely more corroded than the others. Good peace of mind now.:thumbsup:

WOOLUF1952
11-19-2009, 04:52 PM
We are having the same problem with the low headlights turning off all of a sudden on my dad's 04' TrailBlazer. The High Beams work fine. He swapped the relays as suggested and now the low headlights turn on when you turn them on but they do not work on the automatic setting. Also, the fan clutch mentioned is still working properly even when the relays were swapped which makes me believe the relay is ok. What should we try next?

Is the fan actually working? Or is it just turning from friction from the water pump? Did you swap the relay from the fan (#45)? Or the high beams (#43)?

hallebh
11-24-2009, 10:19 PM
So glad I found this site. Thank you for posting info about this problem. The relay was exactly what my problem was! Thanks again!

timothy918
05-08-2010, 11:35 PM
Is it possible to use an analog 12v dc relay in place of the solid state relay used for the headlights? I don't expect a direct drop in replacement. I would make a pigtail to connect it. I don't have a wiring diagram to look at.

I can't get over paying 30-35 dollars for a 2 dollar relay.
Thanks for any help

the roadie
05-09-2010, 12:15 AM
It's not a $2 relay. It's a solid state (electronic) module that can turn on and off hundreds of times a second, where normal relays would die from overuse if used the same way. The faster-than-you-can-see pulsing is used to drive the low beams at 70% power for the DRL function. Owners with HID low beams have to defeat this 70% pulsing because it kills the electronic ballasts. You could fiddle with the PWM signal from the BCM to the module, at the risk of damaging the BCM, because relay coil drive lines (like the one used for the high beam relays) are presumably better protected against the inductive spike that comes backwards when a relay is turned off. The BCM wire that controls the low beam module isn't expecting that spike, and to be safe you'd have to add your own diode clamp protection.

timothy918
05-09-2010, 12:22 AM
It's not a $2 relay. It's a solid state (electronic) module that can turn on and off hundreds of times a second, where normal relays would die from overuse if used the same way. The faster-than-you-can-see pulsing is used to drive the low beams at 70% power for the DRL function. Owners with HID low beams have to defeat this 70% pulsing because it kills the electronic ballasts. You could fiddle with the PWM signal from the BCM to the module, at the risk of damaging the BCM, because relay coil drive lines (like the one used for the high beam relays) are presumably better protected against the inductive spike that comes backwards when a relay is turned off. The BCM wire that controls the low beam module isn't expecting that spike, and to be safe you'd have to add your own diode clamp protection.

Point well taken. I didn't realize DRL was using 70% power. Just call me cheap. Guess I'll spring for the proper relay. Thank you for the help.

Firehound
05-09-2010, 02:09 AM
Interesting... Does having your DRL disabled (by putting tape over the daylight sensor) will you cut back on the rapid cycling, and thereby also extend the life of your relay??

Jay Light
05-09-2010, 02:15 AM
Look guys I've had it with HID's my low beams didn't turn on tonight so I had too follow my GF home with high's only. My Hid's have been nothing but a pain in my @$%. Come morning they r going too be cut into pieces with a pair of wire cutters. Before any one asks yes I've got a relay harness for lows and one for the highs and a drl killer. Junk if you ask me I've spent way too many hours working on them between junk ballests and everything else. When they work they r the best thing in the world but the rest of the time you work on them.

the roadie
05-09-2010, 02:18 AM
Were they cheapie Chinese HIDs or higher quality units?

Jay Light
05-09-2010, 02:30 AM
They r from Jetttstream the relay's and all.

Bay Wolf
06-09-2010, 12:34 PM
I got a Delphi relay off eBay for less than half the price of the Duralast:

300434450871

gtablzr
06-16-2010, 08:47 PM
was wondering if the relays being switched. Will this still only set the dlr's at 70% or run them at 100% all the time.

c22drs
10-10-2011, 08:31 PM
:tiphat:tiphatGreat postings. After replacing the bulbs, checking the fues, and swaping out the "Hi Headlamp" relay, I joined this forum. Who would have guessed that HDM would be the low beam realy. That was my issue. Saved me a trip to the dealer.

Cheers,
Dan

the roadie
10-11-2011, 03:17 PM
...Who would have guessed that HDM would be the low beam realy. ...Whoever named the fuses and relays in this platform should be SHOT.

Non-intuitive names like "TBC 3" which really stands for "Truck Body Controller circuit 3" when the rest of the shop manual calls that module the BCM (for Body Control Module) and what the owner REALLY needs that fuse to be labeled is its real function which is DOME LIGHTS. That sort of stuff.

MoMobile
12-30-2011, 07:19 PM
The lights on my Mom's 2004 Envoy are going crazy! They do something different every time, but usually it's the DRL/Low beam not working problem.

I have switched the 45 and 46 relay (both have a 15016745 part number on them) as suggested but with no luck. I have also put 4 new 10 amp fuses in for the low and high beam circuits and a 15 amp for the HDM.

Sometimes both lights will work and sometimes only one and it will switch from left to right and/or high to low each time for what will and will not work.

What else can I try, could it be the switch behind the knob on the dash? What about the AHS (Automatic Headlamp System), could it be the sensor on the dash for that?

I assume the lights on the top are the high beam and the ones on the bottom are low beam, correct?

Signed,
Crazy lights driving me crazy :weird:

MoMobile
04-09-2012, 02:02 AM
:confused: :duh: :cry:

djmc_72
08-08-2012, 09:45 PM
First post, but have utilized this site many times before. Fan relay, duct motor and more. Great info! So I went to start my '02 in the dark Monday am and I had the left headlight working. I got out while the vehicle was running and got back in and I lost my working headlight. The right hasn't worked in roughly a month. I assumed the plug had melted again and I haven't been to eager to replace for the third time. I found this post and others similar to it on the fourm. I first tried switching 45 & 46. No luck. Checked the bulbs and both have good continutiy. Both plugs are fine. Yes, dielectric grease works! Power and the plugs on high(12v), but not low. Power at High fuses(12v). Power at left fuse low(2.5v) right fuse no power.


Here are my questions:
1. What should be correct resistance for these headlamps?
2. What should be the power at the low fuse on the block?
3. Where to next?

Thanks!

ShannonU
08-24-2013, 12:56 AM
Hello this is my first post. I love this forum, very helpful. I have a 2006 envoy with the low beam problem. I read about changing relays 45 and 46 out with each other witch did fix the problem. So I went to autozone and bought another. It worked for about a month and then lost my low beams again. Again I swapped 45 and 46 and again the low beams came back on. I took the old(new) relay back to Autozone and they changed it out for free. I put it in at the store parking lot and viola I had low beams again. I drove about 2 miles back to my house at night and before I got home the low beams went out again! When I got home I swapped 45 and 46 to check and again my low beams worked. What is going on? I didn't drive at night for a few days and then one night I had too and the low beams were working. Relay 46 was the new relay from Autozone that stooped working a few nights ago and now it's working again so it's not the rely that's bad. What else should I be checking for? I have had no other issues with lights on my truck. I don't think it's related but about a year ago the fan control that controls the AC fan speed from the knob inside(1-5) I lost the ability to turn it up to 5. Settings 1-4 work fine and was told that this was related to a resistor pack behind the glove box. Just thought I would list all issues just in case. Thanks for your help.

MoMobile
08-24-2013, 01:18 AM
The next time the low beams do work, pop out the light assembly and wiggle the wire that connects (also called a weather pack). I found it was this weather pack that was the trouble.

The Mom's Envoy has never had speed "5", so I doubt that is related.

ShannonU
08-24-2013, 01:22 AM
Where is the light assembly (weather pack)?

ShannonU
08-24-2013, 01:59 PM
Once again my low beams stopped working last night and this morning they are working again. Could this be a heat issue? Where is the light assembly/weather pack that I need to shake/wiggle located?
Thanks again.

MoMobile
08-24-2013, 04:29 PM
I will get you a picture today. :)

MoMobile
08-24-2013, 07:31 PM
Head lamp:
Pull up on the two brackets circled in yellow.
Pull the head lamp assembly toward you.

Weather pack:
The weather pack is circled in yellow, it is 4 wires, wiggle the wires with the low beams on and if they flash on and off (as mine did) then you know it is this weather pack that is bad.

Repair:
I got my replacements for $26 each at rockauto.com and take note that the replacement is not colored as the original.

ACDELCO Part # PT1136
OEM part number 15306009

MoMobile
08-24-2013, 07:47 PM
Here, go to this forum, this (link below) is the website that helped me fix my lights.

www (dot) gmt nation (dot) com

Loverotties
08-24-2013, 07:49 PM
Here, go to this forum, this (link below) is the website that helped me fix my lights.

http://trailvoy.com/f23/no-low-beams-daytime-running-lamps-high-beams-only-2858/

Not Found!

MoMobile
08-24-2013, 07:57 PM
That is because trailvoy.com blocks links to gmt nation (dot) com

ShannonU
08-24-2013, 10:02 PM
Ok. I will look at this tonight. Does this weather pack control both headlamps low beams? Just a reminder I never have a problem with just one headlamp, it's always both. Is this a heat issue due to small wires and high current? If so why do they work right after when I swap relays 45 and 46? It would be the same harness just different relay. I know the relay is good because it worked the next morning. Could a wiring heat issue cause the relay to overheat closed? Which would explain why switching the relays would work for a while and the next morning the relays are cooled off and start working again. Could a weather pack cause all this? Thanks for the pictures and instructions above.
Thank you:)

MoMobile
08-24-2013, 10:37 PM
I can't answer any of your questions other than the weather pack because that is all I did to mine.

There are two weather packs, each head lamp assembly has it's own. It has 4 wires, 2 for low (power and ground) and 2 for high (power and ground).

I can only tell you my experience. The lights were going crazy, off and on, one day to the next and never in the same pattern.

Go wiggle the wires on the weather pack of the head lamp assembly, it will take less than 5 minutes and you'll know.

Dr-Wall
09-07-2013, 02:53 AM
Hello from Canada. I've got a 2002 Envoy SLT that I have mad love for. She has 205000km or about 123000 miles. My truck has been great and has just required the usual water pump, ignition switch, and axle seal done. Other than changing all the fluids and plugs I've been impressed with my ride.

Lately the low beams went out. I followed your instructions on swapping out relay 46 for 45 and that worked. I went out the next day to NAPA to buy another relay to replace the bad one and found that it didn't work for my low beams with day time running lights. I returned it and grudgingly went to GM and bought theirs (Actually cheaper than NAPA)...plugged it in and still no lights. I swapped out the 46 relay again and the lights went back on...I put the new relay to 45 and have no signs of overheating...

For fun I swapped out the old relay for the new and nothing. Place the old fan relay in and works again.

Anyone with some ideas? Did I buy 2 bad relays from 2 different places? I don't know if the GM one is bad...truck doesn't overheat but the check engine light went on...

I placed the original relay back to the fans and the check engine light went off but now I have no low beams...what now??

Thanks,
Walter::thx

ShannonU
09-07-2013, 02:58 AM
This is the same issue I have been having with no solution yet. If you find something please let me know. Wish there was more I could do to help.

bigmattdaddy
09-07-2013, 11:30 PM
I am having the same problem... I have a 2006 trailblazer 4.2l, wife called me on the way home and said the low beams don't work, but the highs do. She got home and I checked the fuses, all good. Pulled them out and swapped them with the highs, still no low beams, swapped the relays, and nothing there either....

So, either both relays are bad, (fan does kick in with both relays so doubt it) both low beam bulbs are shot, (not likely, checked the filaments and they look fine) all this with light switch in auto and manual on... I'm at a loss.:confused:

ShannonU
09-08-2013, 05:09 PM
Ok. I took the headlamps off and inspected the wires and connectors (they looked in great condition) and even wiggled the wires while the lights were working and when the lights were not working and nothing changed. What I have noticed is when the lights were not working the relay was very hot. I put the relay in the freezer for 5 mins and put it back in and the lights came back on. So is this a heat issue? Are the wires too small from the headlamps and they are pulling to much current? This is a brand new relay. Could it be a bad headlamp or both headlamp? Would lower watt headlamp bulbs help if possible?

cwboone
01-26-2014, 08:12 AM
First, thanks for the posts. It led me right to the problem. I just want to add that to test the low beam relay, switch it out with the relay adjacent to it, number 45 (cooling fan) with 46 (Headlamp Driver Module). They are the same factory number (15016745). This has all been said. This is new. It can be tested without starting the car. Just turn on the key, put your foot on the break to release the shift lever, and put the shift lever into the drive position. The low beams should turn on, if it is the relay. Auto Zone part number: 20601 -- Duralast $39.99 or 20601VC -- Valuecraft $36.99.

stal9901
01-30-2014, 03:01 PM
I have a 2006 Saab 9-7x with the same issue (no lo beams, everything else works). I tried to switch the relays as suggested, my headlamp relay was fried. Any idea what would have caused this? Also, switching with the other relay didn't get the headlamps to come on.

Loverotties
01-30-2014, 05:23 PM
I have a 2006 Saab 9-7x with the same issue (no lo beams, everything else works). I tried to switch the relays as suggested, my headlamp relay was fried. Any idea what would have caused this? Also, switching with the other relay didn't get the headlamps to come on.

Did you check the fuses?

stal9901
01-30-2014, 05:38 PM
Did you check the fuses?

yes, all fuses were checked and operational

cwboone
01-30-2014, 06:55 PM
Sorry. Saab is Swedish, not even close to a General Motors vehicle. You should try to find a Saab forum to find help on that one.

ddgm
01-30-2014, 10:48 PM
General Motors bought Saab a few years ago and then recently sold them, or allowed them to go out of business. The Saab 9-7x was made in Moraine, Ohio along with the rest of the GMT360 based SUVs. So, a lot closer than you think.

stal9901
02-01-2014, 12:43 PM
Update: Relay melted, caused irrepairable damage, have to replace the entire fuse box :(

Thankful for all of the information in this thread that led to finding the cause

toddster0374
02-01-2014, 08:13 PM
I've got a 2006 saab 9-7x 4.2. I decided to do the capacitor mod and the quad beam with fogs while I upgrade to HIDs to all 6. I did the mods and everything seemed to work fine, with the halogens in. But when I put the HID system in, I lost low beams. There was a fuse blown in the right low position. I replaced it, but still nothing. I swapped the 45 and 46 HDM, still nothing. The fan seems to work fine with either. I DO NOT:( have any power (with a test light) on the #2 prong on the #46 HDM. Looking at the wiring diagram, it seems that this is the first place the power should go to. I have since taken out the mods to be sure they are not the cause. Everything else works fine Just no lows or drls. Yes the HID kit had the capacitors between the ballast and harness. and I have reinstalled the halogens until I find the problem. Any Ideas would be appreciated. Thanks. Todd.

cstoll
06-05-2014, 11:53 AM
I have an 2006 trailblazer and my auto lights went out. I tested the fuses and no power to the headlights. Hi-beams work. Could it be the multi-purpose switch?

bushjc
09-16-2014, 12:24 PM
Having the issue of No Low Beams and swapped the relay for the headlights with the electric fan clutch - Now getting low beams, but also got a CEL soon after swapping the relays.

I have not have the code read yet, but is it possible that having the "Bad" relay in the fan clutch socket is causing the CEL?

Other than taking a chance on the Engine running hot (which it is not doing - kept a close eye on the temp guage), is there any issue that will occur with driving the TB with the fan clutch not powered?

Firehound
09-16-2014, 02:21 PM
If you can, run it into an auto parts store and read the code... I dont have a bad relay to drop in mine, but I do have a reader. Other than that, it wouldn't surprise me if it was kicking a code. The fuel sending unit failing will kick a code even...

dacoach
09-16-2014, 02:54 PM
Had the same problem. swaped relays and decided to drive home and i was fine. Temp gage never moved. I was 2 hours away. Next day went to napa and put in the new relay.

sinaloa
09-16-2014, 05:21 PM
I just found the problem,
it was the # 46 relay, I think is damaged, gonna change it right away, thanx guys:yes:

cwboone
09-18-2014, 08:12 AM
Although you have had no cooling problem with putting a bad relay into the fan relay slot, you are flirting with danger. They don't have electric fans for nothing. And when temp sensors detect high temps, they send a signal to turn the fan on. So far you have been lucky. Potential consequences? Overheating your engine -- Blown head gasket, cracked head, etc. Very expensive. Advice, bite the bullet and buy the new relay. It is not worth the gamble.