So I got this idea of hanging either a radar detector or Dash cam from the mirror. I need 12volts and I dont want the cable hanging down to the cig lighter. Seems like the best option is to get power from the rear view mirror. I really really dont like splicing into the factory harness. So what are my options? Make a really short cable that has the 16 pin connector on each end and the power hanging out he side. Before I get to involved with this, has anyone done this before, are there store bought Tees for this application?

 

Don't mess with the power to the mirror - just hide the wires under the headliner, and down one of the door posts behind the plastic covers. Keep it simple.

Just be careful near the airbags in the door posts (if so equipped).

 

For one thing the map lights run through the RetainedAccesoryPower system.

 

X2 on both posts above!

 

I was going to tap 12V from the 16 pin, 7 wire connector to my LS mirror, (it has 3 On Star buttons) so I disconnected it to look at the color codes. I started the car while it was off and got an ESC and ABS lights. Turned it off, plugged it back in and the ESC light was gone, the ABS light still there but it will go away soon I imagine.
Anyway, since even disconnecting it seems to have bugged the computer controls I thought I would ask on here about the pinout for the wires I found.
I have a Black, Blk/Wht, Yellow, Pink, Grn/Blk, Blu/Wht, and Green. Would any of these have switched 12V? Which one is ground?
All I would power with it is one tiny LED.

 

OnStar is connected to the computer. Wait until you try to unplug the OnStar unit.

Does this help? Some pins are obviously not connected.

 

Wow, thanks a million, Donbrew! I may do nothing with it, but at least now I can figure out what's what. Anything I did I would make sure it is easily un-done in case the comp has a hissy fit.
After what I saw this afternoon I decided to leave the sleeping-dog-OnStar lie.

I dropped the air pressure in the rear tires (over-inflated) once and got the same two warnings.
ESC and ABS. Apparently, any and all changes, no matter how dissociated or inconsequential, will disrupt the ESC and ABS universe. Or at least the GM designers thought so.
Thanks again, that looks like just what I needed.

edit: with a minute to give it a look, I think I need just the pink and the black on pin 8.
Nice. Some of the others are computer signals and whatnot, best not tampered with.

 

Pin #13 ign voltage is on BCM fuse #16 10A.

The ABS/ESC will come on if one tire is a lot different from the others; the diameter would be different, causing a wheel speed difference.

 

That's cool, I'll only borrow 3 to 5 milliamps. He'll never notice.
haha
But if that fuse were to blow, I'll know I did it. Thanks for that info, too.