Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Welcome, I'm Chris (aka Moose), my normal schedule online is around lunch and after dinner till early morning.
Was this a prior police or emergency vehicle?
Here is the wire diagram. https://dl.dropboxusercontent.com/u/90220402/impalalights.pdf
This is going to be a BCM or PCM module issue. They control the back up lamp relay. Do you have access to a diagnostic tool that can monitor the inputs and outputs on these modules?
Thanks for using Just Answer, and rating me so I am compensated, Chris
We need to monitor the transmission range sensor reading the PCM is getting while in reverse to see if that signal is changed when braking and not braking. The only ground I can see possibly related is on a transmission to engine mounting bolt/stud next to the starter.
A tech 2 diagnostic tool is needed to monitor this signal. It is not a wire test since it is a data communication wire.
Cleaning connectors will not hurt.
A module has many responsibilities. You can lose just part of it and the rest will remain working.
Hello again Chris here,