Thread: 2008 Grand Prix Question

Ok, so i have been investigating on why my car did not have Onstar, since it was supposed to be standard on my car. GM customer service said that when the fleet order was processed, they remove onstar from my car. Now today, i found the wiring for the rearview mirror still up in the inside roof cover. Can i get an Onstar mirror and the antenna and hook onstarr back up on my car or is it a little more difficult than this? Thanks!

If you have the 2 white plugs that would go to the onstar module up inside the dash it will be very easy. Just look under the center of the dash ahead of the center console and you will see them if you got em. Just above where the wiring harness goes to the center console.
If you got those two connectors you may even have the antenna wiring as well.

I added it from scratch on my 04 by changing out the dash harness while i was adding other options and could not get onstar to recognize my car as it really was since the module was from a wrecked car, however im sure if you get higher up tecnical at onstar or maybe the dealer reflash the onstar module you can get it to match your vin and everything. Just my 04 ended up getting wrecked so i nveer got that far.

the wire's are up in the ceiling by the rearview mirror, evidence that there was the mirror there.

I wouldnt say it was there, Just it was left out at the assembly line, you can confirm this by looking at the service parts label under the carpet/spare tire cover. If you have RPO code UE1 it did have it, if you dont have this code and have something like UE0 or similiar it was left out to begin with.

All roofharnesses that had the lamp group option that included the rear interior lamps with switches automatically come with the plug just up inside the headliner.

You have the headliner harness for onstar which you confirmed, The body harness already has the onstar wires in it already since i know they do from experience, so now the last thing to confirm is if the dash harness has the wires which is why we need to know if those two plugs exist under there.

Let us know what you find

If you have these two plugs you will need mainly the onstar module, mirror, and antenna. For the antenna you will have to make the mounting holes in the roof to accept the antenna unless you have an xm antenna which case there would already be holes and just need to swap the antenna.

Ok, i found the white connector where you said it would be, but i found only one, behind and under the dash. Is there another spot where the other connector would be? Thanx for the help.

Moved.

Try to post in the appropriate section.

Thanks.

Moved to what? i have not been on a forum before. sorry.

I moved your thread to the appropriate section for the type of thread you've created.

Helps other people find it easier.

Did you have a look to see if the other one is taped up somewhere near? how many pins does the one you have got?

Does anyone have a diagram of where all the wiring for a 2008 Grand Prix? Like the Onstar Wiring, and where to look for it all at? Thanks!

PM me your email address and i'll send em over to you, i got connector pinouts plus diagrams.

Ok, i am not going to do the onstar thing for a while, due to it's expensive. I was wondering if anyone knows how to hook up the compass and thermometer in the grand prix. I have the 3 buttons right now. Do i need to have the 5 buttons for it to work?

The 5 button DIC with temp and compass is very easy to do.

All you need is the front temp sensor that goes behind the bumper/grill,
the compass sensor that goes under the rug under the back window, and the 5 button dic with the matching trim.

The best place to get this stuff is from a junkyard locally as most online sellers realize the demand and the price is usually 200+ dollars.

If you cant get the temp sensor off the wrecked car due to being smashed to badly the dealer has em for about 10 bucks. The car has all the wiring already regardless of what trim it is.

I know of one person who couldnt find the connector in the back for the compass module but im guessing it should be there, To look for it you can reach your hand in from in the trunk where the audio amp would have been between the two speakers and feel around for the unused connector, Its around the left speaker.

On the onstar topic did you manage to find that second white connector?

Yes, i think i did find the 2 connectors, but the cost of having to put the Onstar items on was too much. On the compass thing, i found the connector, but not the wires in there. Also, how do i find the temp sensor? do i have to pop off the grills to get to it?

For the locations of stuff morad parts company has a guide on the ebay auction which can be had here, just click open when asked;

http://www.moradpartscompany.com/pic...%20install.doc

theres a pic in there showing the sensor location and describes it, howveer if you still cant find it i'll grab my camera and get a pic showing where with part of the front bumper in the pic so youll get a better idea.

Ok, again, thanks for all the help. I went down and looked in my car, and i found the compass and it is already wired in. I think i found the temp sensor in my bumper and it's already hooked up. Just to clarify, how would i remove the black plastic grille on the front of my car, just to be positive? Also, i have the passenger airbag sensor in my trim plate. Would that make it any harder or not?

Should be able to getto it just from the trim plate around the latch, just pop the plastic snaps. the airbag sensor is bolted right to the metal to it wont be affected.

For the compass sensor in the back are sure its that and not the keyless entry module? just that they are in very close location to each other.

If so you should just have to get the 5 button and trimplate and all good to go.