backup lights

The reverse lamp relay is controlled by the rear integration module, based on a bus input.With the proper scan tool, you could perform a function test of the modules capability to control the relay, and that would simplify the diagnosis. The cause could fall into a couple categories. A control problem, either by the vehicle not indicating reverse, the bus system not telling the RIM it is not in reverse, or the RIM not controlling the reverse relay. If you can manually verify that the reverse relay is activating, then you can move down the line. Another possibility is a broken wire at the rear compartment harness, at or near where it pivots when the lid is opened. Included here is a location of C400 which the signal and ground wire pass through.


(Domestic) (3 cavities) Body harness to the backup lamp harness, right rear corner of the rear compartment near the tail lamp


If there is power on the light green, and ground on the black(pins a and b respectively), you have verified that the relay is controlling and the problem lies between that connector and the backup lamps. Concidentally, are the license plate lamps also out?

thank you,although i don't understand this.the license plate lights do work.

I am having a very similar issue. I have a 2000 Deville base model. All the lights on the deck lid are not working properly. The license plate lights flash when I use the key fob to open the trunk, but do not work when the lights are turned on. The back up lights do not work at all. The third brake light is not working either. The left and right brake lights work as they should. I have replaced the license plate bulbs and back up light bulbs with no success. Where should I look first?