4WD Question

[HayChalet]

Hello! This is my first time posting and I have a 2003 TrailBlazer LS and have a question about a light. When my truck is in the normal 2 wheel drive it has a little light that stays on and it flashes and changes when I change it to 4 wheel drive, etc. Well the light has been off for a few months now and I was wondering what that meant? Is it just a fuse? Does this mean that the 4 wheel drive won't work? Of course it's calling for our 1st big snow fall tomorrow 6-10 inches. Thanks for your help! :duh:

[ylab]

Welcome aboard!

Short of bringing the vehicle to the dealer, what you can try is to physically pull the transfer case (4x4) fuse for 10-15 seconds and then replace it. (Check that it isn't blown out when you pull it). This *might* reset the actuator controller and get you back up and running......odds are slim, but just sometimes this can fix it. - If memory serves me correctly, the fuse for the transfer case is in the box under the rear driver side seat.

(I'll go out in a few minutes and see if I can tell you which fuse it is, don't recall off the top of my head).

If that doesn't fix it, you most likely have a bad switch. See if you can hear the actuator motor when you shift between 2-HI & A4WD with the window down and vehicle idling in park. (You should hear a momentary electric motor sound).

[the roadie]

Hello! This is my first time posting and I have a 2003 TrailBlazer LS and have a question about a light. When my truck is in the normal 2 wheel drive it has a little light that stays on and it flashes and changes when I change it to 4 wheel drive, etc. Well the light has been off for a few months now and I was wondering what that meant? Is it just a fuse? Does this mean that the 4 wheel drive won't work? Of course it's calling for our 1st big snow fall tomorrow 6-10 inches. Thanks for your help! :duh:

When you first turn on the key, the dash goes into a lamp test mode and everything turns on for a second. This includes the four lamps for the four drive modes. Are all four of these lamps out (meaning a fuse, cable, connector, or module problem), or just the 2WD (which might be as simple as one lamp dead)?

If the transfer case control module was dead or throwing a code, you'd normally get the idiot light on the dash saying to "service 4WD" as an additional hint.

I take it when you put it into 4LO mode when in neutral and going less than 5MPH that you don't get the traditional clunk as the transfer case changes ratios?

And welcome to the forum! I have to give you kudos for including an avatar for a first-time post. Some regulars haven't broken the code on that one.

[ghoster]

Take it out, put in 4 wheel drive, and test it out! Thats the fun way to check. Could be something as simple as the light burned out, or the switch could fail. Lots of stuff. oh...and welcome to trailvoy!:cool:

[Blulytes]

Hay, Welcome...
As for the lights... I assume that just the 4wd light is out? or are all those lights out?

The only way I can tell you definately if your 4wd is working... without lifting the car up... is:

1. Go to a parking lot, or somewhere you can make a big turn
2. put it to 4wd hi.
3. Turn your wheel to lock and accelerate very gently.

If you feel the truck start to buck, your 4wd is working. If you can go around in a full circle without feeling hesitation and a buck... you are out of luck!

(too much rhyming going on there)

[Dave]

Early model trailblazers had an electrical problem with the transfer case. If the light doesn't come on when you switch it to A4WD or 4HI I wouldn't bet on having more than RWD in the snow.

If the light is off in 2WD, it sounds like a transfer case problem. Depending on your mileage, it might be covered under warranty. I think the switch itself was the main culprit.

[tahawus84]

your cute :)

[ScarabEpic22]

Welcome!

Props on the avatar, I only put one up after I had ~400 posts or so!:duh:

And for the problem you are having, Ive had it too. Mine seems to come and go once or twice a year, but I just pull the fuses in the fuse boxes for a little bit and it all works again. Really weird, but every time I have needed 4WD (going skiing), it has worked.

[eaterb]

Well, we had a snow storm here last night. I tested the A4WD and 4hi last night. I am 99.99% sure it was working, but no lights flashing when changing modes. I checked today and I do hear the electric motor when switching between modes, I just do not have the light flashing, etc on the knob. I checked the fuses...any thoughts on what else to check?

Thanks,

Brett

[Magnum]

I just noticed that I have this same problem. However, I tested out the 4X4 today (in the snow)...and it is not working:cry: . I am going to test the fuses. Hopefully this helps...if not, it is off to the dealership for repairs.

[eaterb]

Magnum,

Could you hear the electric motor?

[Magnum]

No I couldnt hear the motor cycling. I have an appointment at the dealer in about 45 mins. I have done some research on past threads and it would appear that the TCCM (transfer case control module) is to blame. But we will see. I ll report back on the diagnosis of the problem.

[eaterb]

Thanks. Keep me posted.

Man, this is the 2nd major issue I have had in the last two weeks. First, the rear oil seal goes and now the possibility that the 4wd might not be working...yikes...I doubt the dealership will squeak a 2nd major repair in under the used car warranty...

[Fishhunter911]

Thanks. Keep me posted.

Man, this is the 2nd major issue I have had in the last two weeks. First, the rear oil seal goes and now the possibility that the 4wd might not be working...yikes...I doubt the dealership will squeak a 2nd major repair in under the used car warranty...

It shouldnt be a major repair, from what I hear it is real easy to do, and a couple hundred bucks.

[2002BlkLTZ]

your cute :)

:iagree: :yes: :drool:

[Fishhunter911]

:iagree: :yes: :drool:

You guys skeered her away already!!! she hasnt been back!!:crazy:

[Magnum]

Just an update......

The dealer called and said it was the TCCM (transfer case control module). This is consistent with the problem that everyone else is having. Go figure!

[Fishhunter911]

Is it going to be covered???

[Magnum]

Yes it will be covered....because I had purchased the "total plan" extended warranty when I bought the truck. I pick it up tomorrow and I ll update you on what the costs were to replace it. (I dont think it is a long repair...but they had the vehicle apart and had to order something so they decided to give me a rental).

[Magnum]

***Update on diagnosis/repairs***

The dealership ended up replacing the transfer case control module ($503.25 Canadian) as well as the 4wd selector switch ($48.30 Canadian).

It only took them 2.5 days:crazy: :rolleyes: . Apparently their internet was not working and they needed it to access the instructions to do the necessary repairs. Since they had the vehicle apart they set me up with a rental..4x4 Chev P/U. All is in proper working condition now:thumbsup:

[Fishhunter911]

congrats, I am glad they fixed it for you!!

[GeorgeJL75]

I also have an 03 LS and have had this happen to me several times. Each time I thought the fuse had blown but it hadn't. After removing and reseating it I start it up and the light is back on. The AWD and 4WD is disabled if the light isn't on.