Currently, my reverse switch is working completely backwards of how it should. When it's running and in reverse, the reverse lights are not on. When it's not in reverse, the lights are on. Also, when I shut the car off, I get the "Switch to reverse" message when in reverse, but not when it's in any other gear or neutral.

Backstory:
A couple weeks ago, when I shut the car off, it wouldn't register the it was in reverse and shut off the electronics. So, I disconnected the battery so it wouldn't drain until I could take it to a repair shop. When I reconnected the battery, it was stuck in accessory mode. It wouldn't start and still had "Switch to reverse" message. I had it towed to the dealership.

The dealership spent a week screwing around and getting nothing done. Finally, they changed the BCM and the reverse switch (in the transmission) After programming the BCM they said it worked. Now I have the above mentioned issue of the reverse switch being completely backwards.

What else can I check?

 

Would check the switch in the trans.

Hence shove the ball in, and should have continuity through the two pins on it, and when you release the ball, should not have continuity on the pins.
Now leave it out of the trans, go to shut the car off, and push the ball in to make sure the car is seeing the switch with continuity through it.

If it working fine outside the car, but going funky when installed back in the trans, problem is not the BCM or switch, but lever in the trans that pushes the ball in when the car is shifted to park. Hence this quick test should have been completed before the BCM was replaced, and my guess, its the trans that has to come apart to correct /replace the off set lever isntead.

Here are the forward offset levers, Vette is on the left, F-body on the right.
Note the little dongle on the Vette one for the reverse lockout solenoid to contact. And on the 2005, the dongle is a little different, since it has to contact both the switches used only on the C6 2005 trans (2006 and up, only has the one switch).



P.S, Good luck on getting your money back on the Good BCM that was replaced for no reason. Hence any horse trading to put that against the Trans work, will just end up with them jacking the price up on the trans work isntead.

 

Thinking out loud here, I recently pulled the trans on my 05 and noticed the two switches for reverse. They are both purple connectors IIRC. Could it be that you have them reversed? It would just take a minute or so to test that out.

 

Thanks for the great information!! I ordered two switches. When they come in, I will test everything. Obviously, I'm hoping it's just the switch

 

Thanks for all the help. it's all up and running now. Looks like the stealership only changed one of the switches. Not sure if it needed the BCM, but nothing I can do about it now