Reverse wire issues with GMOS-08 and Pioneer AVH-4000NEX in 2005 Equinox

[hurnik]

Okay I have a 2005 Chevy Equinox LT with Bose/Premium sound and Onstar.

I had an older GMOS-08 and ASWC with an old Pioneer HU. Worked fine, but wanted to update with something that worked with Android.

So I got the newer GMOS-08 and ASWC-1 and the Pioneer AVH-4000NEX. Also got a BOYO reverse camera.

The Pioneer unit is all wired and works fine. Metra says that their green/purple wire supplies +12V DC when the car is in reverse and that it should be connected to the reverse on the HU. I have done that. Camera is plugged into accessory power.

Camera does work. If I force the Pioneer to have rear camera on all the time it works. But the Pioneer unit will not switch to rear camera input when the vehicle is in reverse. I checked and there's no power from the Metra harness on that cable.

I have tried switching polarity on the HU, but if I switch from battery (+) to ground (-), then the stupid HU puts the camera on all the time and you cannot use any of the HU features (you literally have to disconnect the battery to reset the HU back back to battery).

GM techs on ask.com seem to think that there is NO voltage through that part of the car, or the GM LAN interface, and that you need to tap into the reverse lights or the rear view mirror, over by the driver's side door panel (ack).

I assumed that a multimeter test I did on the green purple was accurate for no voltage, but maybe I did it wrong?

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[CrossoverOre 10+ year member]

as long as the neg lead of the dmm was to ground and the other side to the wire then thats how you test. sometimes if you are trying to go through insulation you might not make it all the way to the bare wire and get false readings. I would try unplugging everything and reset the interface. The instructions also say to cycle on for 30 sec then back off the first time you turn on. Then you turn it back on and test the install. You could try without the aswc plugged in to see if that makes a difference. The other thing might be to try and reinstall the old interface and see if that one works. Or finally run to the reverse wire of the vehicle and not use the interface. But there has to be voltage though that part of the car of the stereo would not turn on to begin with.