Is the Compass on rear view mirror built in the the mirror or does it require wiring to a computer, etc. I found one in a junkyard and want to now if I need all the wiring and some computer module too. Does anyone know?

 

If I remember correctly, just after the HHR was introduced, several people purchased the compass mirrors directly from the supplier to GM, and installed them. I think they wired right in.....so they would be self contained.

Some other members will probably check in also.

 

All components of the compass are inside the mirror. It only needs power to work.

 

Ditto.

 

Thanks. I did find one at a bone yard. Also got the wiring harness all the way to the back of the car that ran under the headliner.

 

That sounds like a rather tedious installation. I'm glad mine came with it originally. I added a factory optional auto-dimming mirror with compass to my son's Nissan Sentra. The wiring was already in the car - installer took 15 minutes to do it while I watched! Next, doing same thing to a girlfriend's Nissan Versa (unf the optional auto-dimming mirror didn't have a compass).

Of course, once you get it installed, it has to be calibrated. There's the mystery of determining and setting what zone you are in, and then the driving in circles....

 

Huh !!! Takes like 10-15 seconds. Zones are illustrated in the Owners Manual and you only need to be close.