actually let me update -
pin 8 - is common
pin 6 - is the wire from the previous mirror than read .25v
pin 1 - is the 12v+ on all the time
pin 13 - is the autodim/ compass 12v+ switched.

got mine working yesterday and love it. so i have autodim/compass/maplights that dim

 

I ran across this awhile back (not all versions of mirror use all pins)...

1 = Grey = not used
2 = Bare = Microphone
3 = "Passenger Air Bag on" notification (some GM trucks - ground pin to activate)
4 = "Passenger Air Bag off" notification
5 = auto day/night signal from LH outside mirror (use w/ pin 16)
6 = Brown = Temp probe connection
7 = Green/Black = Temp probe connection
8 = Black = Ground (Common to Pin 9)
9 = Light Green = Reverse Dim Inhibit
10 = Gray = Microphone
11 = Dark Green/White = keypad signal (out)
12 = Light Green = keypad +5v supply (in)
13 = Yellow = +12V switched (ignition)
14 = Yellow/Black = Green LED signal
15 = Brown/White = Red LED signal (apply 12v to light LED)
16 = day/night signal to LH outside mirror

 

Great! Thanks to everyone for the help. I have two mirrors, one a full auto dimming with OnStar, and one standard mirror with OnStar but has manual day/night. Neither has map lights. I'm putting both up for sale in the classified in about one hour.

 

Map lights, Compass, and temp on an auto dimming mirror? What part number do I need to order? I wonder if this will fit my 2010. Anyone have an idea?

 

I enjoyed that option on my last car, but my '06 HHR LT1 did not have that option available and I don't think the '10 LT1 has that as an available option. I think it comes standard with the LT2.

It seems difficult to special order an HHR and get a good deal any more.

 

My '08 2LT has onstar, maplites,auto dimm, and compass. Came standard on my package.

 

wonder what the part # is, and if it will work on my 2010.

 

ok, for a 2010-2009 Auto dim mirror with Onstar P# is 15787972, and runs $239.80 from GMPartsDirect.com

 

put one in my 09 LS and it plugged right in. I think the part # is the same as a trailblazer. I found one in a junkyard and installed it.

 

Did anyone ever figure out the GM part number for the mirror pictured above? I'm looking for this exact mirror with the Auto Dim feature along with OnStar, Map Lights, and the Compass. I have a mirror here in front of me with GM part number 15787972 and it does not have map lights. It also has the light sensor in a different location (In the top center of the mirror) rather then down to the left of the power button like the one pictured. The one I have here also seems to have the compass equipment inside of the mirror, rather then stuck to the mounting base like in the picture above.