I also have the in-mirror display w/out onstarcontrols(I have onstar just no mirror controls) & no-nav, cut green wire pin 9 on mirror wiring harness, wire 12v with switch to pin 9, flip swith to power on reverse camera & display. Works like a charm. For safety I would suggest using a diode and an in-line fuse.

 

Well in my 2015 silverado I keep a gang box in back and can't utilize rear view, in my 2016 Gmc van I don't have windows so the camera would be very useful. Now that you have the way can you tell me how to do it? Or did you just want to comment?

 

My back up camera in the mirror has a mind of it's own. Sometimes it works and sometimes it don't. Any suggestions?

 

It's a 2010 lt also

 

if you want the camera is always on , you need to connect the camera to a power source that is always on instead of reverse light .

 

Well this was half the battle I found if you power Pin 9 you get a back up display as mentioned. However the catch is its only active for about 2-3 min, then the power button will flash and display will go dark. If you are lucky you can press the power button long enough to get the flashing to stop, but if you try to power it back on you get nothing. The 12v power is still at the pin 9. I also tried jumping pin 13 (12v when key to on) with a diode to Pin 9 this worked as a 12v source but I got the same condition after a few min. the display was useless. Only key off and back on will fix the display.
We are missing some piece of info to get this working completely. Im sure something else needs to have power for this to work completely. If i get some time im planning on taking the rear panel off to check the voltage on the camera Form what i can tell it always has power but if Pin 9 is a signal for the BCM to power a relay at the camera i can see why the circuit times out after a few minutes.
Dose anyone have the Pin out for 07-14 mirror or better yet the whole circuit camera to mirror?

Every other forum out there has some special person stating why it should not be done. keep those comments to yourself. Lets keep this topic constructive and informative.

 

That is an unhelpful, irrelevant comment.