Trailblazer: Need switched 12V on top of windshield

[New to TB]

Hello guys! I just took delivery of my new TB LT on Friday, I love it as I knew I would! My father is on his second so I had some experience with the truck.

Over the weekend I mounted a GPS in the upper left hand corner of my windshield like I usually do. Right now I have the power wire running down to the center console and plugged into the accessory outlet. I'd like to get rid of this and have the wire hidden and it hardwired into a switched source (so it goes on and off with the car) like I did with my past cars.

My last car (Passat) had the fuse box on the side of the dashboard where the door closes against, so all I had to do was run the wire down the A-pillar into the fuse box. In my new TB, there seems to be some type of panel in that position, but I can't seem to get it opened, and I am sure there is no fuse box in there (altho there is probably a switched 12V I can tap into somewhere down there).

So my options are to either get the wire down the A-pillar and into the dash somehow, or run it over to the center overhead console. I have a sunroof, OnStar, and rain sensative wipers so I assume there is a switched 12V source up there, correct?

Anyone know about the wiring scheme in the TB and willing to give a newb some advice?

I was happy that my truck came with XM built in, one less gadget to wire up and have hanging around the interior. But I need my GPS for work and I hate having the wire running across the windshield over the mirror and down to the accessory outlet. I'd like to hide it and have it connected to a switched source so I don't have to turn it on and off myself (lazy, I know ).

Thanks!

[MoJoe]

If your GPS has a on/off switch, then just run it down the pillar, and into the dash area. There are plenty of 12v sources there. For my head unit, I use the rear window wiper switch 12v. It only powers on when the ignition is in the start position. If you want to be able to use the GPS while having the no key in, then just use the accessory plug wire and splice into that with an inline fuse.

To get the headliner down far enough to run wire behind it near the windshield, going either way, just take out the sunvisor clips with a Torx T-20 and it will give you enough to snake the wire in there. That is how I just ran my temp/compass mirror.

That is how I would run it.

Oh, and most importantly WELCOME :D

[New to TB]

Thanks for the reply!

How do you get the wire from the A-piller into the dash area?

Thanks for the welcome! I've been looking for a dedicated TB/Envoy forum for a week, I finally found this place by being referred from another forum.

[MoJoe]

Thanks for the reply!

How do you get the wire from the A-piller into the dash area?

That will require pulling the front dash trim ring off. There is an article some where on here to remove it I think. Very simple. I will look. You will not need to remove it completely if you are careful, just pull it off and leave yourself enough room to snake the wire and crimp it inline to the 12v one.

[MoJoe]

:mad: I can't seem to find a good one to show where all the screws are. If someone could chime in with the URL of what I am looking for :undecided ;) If not and you need some pics, let me know and I will take mine back off for you and get some pics. :)

[New to TB]

I appreciate the offer, but I don't want to see you take it apart again. When it stops raining I'm gonna head outside and put my new truck under the knife ;)

Thanks again!

[02EnvoySLE Guy]

I appreciate the offer, but I don't want to see you take it apart again. When it stops raining I'm gonna head outside and put my new truck under the knife ;)

Thanks again!

Don't feel bad. I had the engine of my Envoy half torn apart within a half hour of being home from the dealership!! :laugh:

Can't help but get the bug for mods when you own a truck like this! :D

[MoJoe]

Don't feel bad. I had the engine of my Envoy half torn apart within a half hour of being home from the dealership!! :laugh:

Can't help but get the bug for mods when you own a truck like this! :D

I got bit by the bug the moment I turned 16 :D

[New to TB]

That will require pulling the front dash trim ring off. There is an article some where on here to remove it I think. Very simple. I will look. You will not need to remove it completely if you are careful, just pull it off and leave yourself enough room to snake the wire and crimp it inline to the 12v one.
Another question about this. What is the "Front dash trim ring"? The piece around the instrument cluster?

Is there a way to get the wire from the A pillar to underneath the dash (and connect it to a switched 12V source there) without having to take the front dash apart?

[Jman423]

I did something similar to what you want for my radar detector. I ran the wire from the fuse box under the backseat, up the pillar between the front and back door, and then inside the headliner around the front to where it drops out to the radar detector. It sounds like its complex, but its not at all, it took me maybe 15 minutes to run the wire. Then I just tapped it into one of the ignition fuses that goes off with the truck. So from start to finish, the whole project took maybe 30 minutes, you can't see any wires at all, and its not a crappy rig job. :m2:

[New to TB]

I did something similar to what you want for my radar detector. I ran the wire from the fuse box under the backseat, up the pillar between the front and back door, and then inside the headliner around the front to where it drops out to the radar detector. It sounds like its complex, but its not at all, it took me maybe 15 minutes to run the wire. Then I just tapped it into one of the ignition fuses that goes off with the truck. So from start to finish, the whole project took maybe 30 minutes, you can't see any wires at all, and its not a crappy rig job. :m2:
How did you get the wire from the B-pillar to the front? Did you have to pull the headliner off, or were you able to just tuck it in?

[Jman423]

How did you get the wire from the B-pillar to the front? Did you have to pull the headliner off, or were you able to just tuck it in?
Its all tucked, very clean!!

With this proceedure, you don't have to take anything apart. If you do like I did, I popped off the plastic floor panel at the back drivers side door (for lack of whats it really called) and fished the wire under the carpet so its not sticking out at all.

[MoJoe]

There is also the way of just taking taking the pillar panel off, and once that is off you will be able to see to the floor through the dash, just feed the wire straight dow using a 16" piece of a cut off hanger, and probe the wires below the dash to figure out which one is a 12v switched or constant. Do you have a test light or meter?

[New to TB]

Yup, got a couple of multi-meters lying around.

I assume the A-pillar comes off by removing that round plastic cap and whatever type of fastner is underneath it?

What I would really like to do is tap into something in the overhead console. My GPS's (Garmin) power cord has a speaker at the end for the voice guidance, it would be nice if I could hide that plug/speaker inside of the overhead console. There is some type of vent in the console which seems to be perfect to let the sound out without having to see the eyesore speaker.

The way I had it in my old car, the plug/speaker was hidden under the dash and I couldn't hear the voice guidance too well unless I was going very slow and the radio volume was low. If I can, I'd like to avoid that in the TB.

So... I have a lot of thinking and exploring to do, I'd like to do this the right way the first time.

Thanks for all the help guys!

[henrywp]

The map lights that are in the overhead (the 194's) have two sets of power going to them. There is a line that is fed from a relay which is activated when the doors open up and then there is a switched 12V power source that is fed to them so that when you push the on/off button they light up. I would tap off of them for my power source.
I'm not sure as to how many amps you're needing, but you can get about an extra 2 amps of available use if you replace those 194 bulbs with the led equivalants. Anyways, just food for thought.

[New to TB]

The map lights that are in the overhead (the 194's) have two sets of power going to them. There is a line that is fed from a relay which is activated when the doors open up and then there is a switched 12V power source that is fed to them so that when you push the on/off button they light up. I would tap off of them for my power source.
I'm not sure as to how many amps you're needing, but you can get about an extra 2 amps of available use if you replace those 194 bulbs with the led equivalants. Anyways, just food for thought.
Are you sure that it's a switched 12V source? I thought those lights worked even with the car off?

[Tommy]

Wiring Diagrams are located in the resource section. Maybe they will help.

http://www.trailvoy.com/index.php?page=resources :)

[henrywp]

They will work until the alarm is set and/or the 20 minute timeout is complete and then the power source is removed. Another option is to tap off of the cigerette lighter outlets. They work the same way. That's what I used for power to my mp3 player as opposed to using the power feed that goes to the radio.

[XTREEME]

I know you can pull switched power from the rearview mirror if its got onstar and a compass for sure, but I just don't remember what color is what. The wiring info link above does not mention it.

[MoJoe]

If you have the rearview mirror with compass and so on, the poer is pin #1 I just hooked mine up.

[New to TB]

I couldn't find switched power in the overhead console. There were even 2 12V wires going to the sunroof switched, but those stayed on even when the key was out of the ignition and the alarm was armed.

I ended up running a wire from the fuse panel in the back into the overhead console, then I put the GPS's speaker behind the grill in the console so it could be heard.

Worked very well, thanks guys!