Hey,

So I was told that I will need to run a couple of wires into this unit. One is the parking brake sensor, and one is a speed sensor wire.

Assuming I do not use any of the hacks that remove the need for the parking brake sensor, any ides how i would get access to these sensors? I have a 2007 Pontiac Grand Prix GXP.

Crutchfield will tell me through their tech support once I buy the thing...But I'd like to know if I have to go tearing apart more of the dash to get to these things. It might change my mind about doing it altogether.

Thanks,

Joe

The parking brake pedal will have a small switch that is depressed when the brake is not set. One side of the switch will be ground and the other will be +12 volts, connect the parking brake sense wire to the +12 volt side of the switch.

I am not sure which exact wire is for the speed sense in your car but it should be located at the ECM.

You might also be able to use this (probably require it require it actually), designed to add aftermarket radios to your vehicle.

http://www.logjamelectronics.com/pacclgmrarea.html

since the 2004 - 2007 Grand prix had the option of factory navigation system is should allow all connections needed from the factory wiring harness including VSS and parking brake sense.

more PAC adaptors in case you want to keep factory steering wheel controls etc or if above dosen't apply to your vehicle (if you have OnStar)

http://www.pac-audio.com/productSearch. ... &YearId=18

Thanks for the info.

I was planning on getting the GMOS-4 from crutchfield which does the same thing as the PAC unit. However neither of them provide the 2 wires I need.

Obviously the wires I need are in the connector that is plugged into the factory radio...cuz the navi disables stuff when I start moving.

Shouldn't I be able to pull the wires out of the factory connector and use those?

Thanks,

Joe

probably not, they are not typical ground or +12v wires, they are basically like a network wire that exchanges information with the car's engine management computer, the PAC interface translates those signals into something that aftermarket units can use. I didn't use the PAC interface for my Mustang but so I ran the VSS wire to the front of my car where the ECM computer is and attached it there. The parking brake on my car is the hand brake so I attached the parking brake to the +12v side there. Had I used the PAC interface I would not have had to do the manual connections.

Oh I see. So by using the 12V on the PAC, you're just simulating the parking brake always being on, for instance...since the pin on the PAC is constant 12V.

I'll have to see if the GMOS thing has the same feature.

Joe

It doesn't simulate anything, it translates the actual information into a format that an aftermarket unit can understand and use. ex; IF it does indeed contain the parking brake signal, it would tell it that it is on when it's on, and off when it is actually off.

I did just take a closer look and it looks as though the VSS and parking brake etc are not available from the factory harness according to the PAC instructions, looks like you will have to find them and hook them up manually, however an adapter is still required to retain certain functions such as door chime, OnStar and others, perhaps a different adapter can provide the signal but I'm not 100% sure, as there is a "class 2 data" wire indicated in the factory harness, perhaps one of the installers in this form can shed a little more light on the subject.