Initially, we had problems with the lighting not changing to night mode when it got dark. We would fiddle with the rear view mirror button and the lights would shift. I removed the rear view mirror and the TWO electrical connectors, blew them out and reinstalled them. The problem seemed to go away as the lighting functioned as it should.

Earlier this week, while driving at night, the lighting system cycled rapidly between night & day mode. It sounded as if all of the switches and relays under the dash were operating on their own. I had not struck any unusually hard bumps or anything else to jar the vehicle. While parked, I wiggled the 2-wire connector wires and found that I could reposition the orange (hot) wire and duplicate the condition.

I followed up by checking the voltage as per the GM repair manual. The voltage at the connector did not fail regardless of how the wire was moved. Based on this, I decided the connector was working loose or re-positioning while the vehicle was in operation.

I copied 3 pages of the GM Service manual that showed the back of the mirror (with the 2 connectors), the routing of the wiring harness, and the connector end view (which included the GM part number). Armed with this information I visited 2 different dealerships, a Cadillac dealer and a Chevrolet Dealer. Neither parts salesman could locate the connector in their computer system. The Cadillac dealer called a GM 800 number and found that the part number listed in the GM service manual was no longer valid and there was NOT a substitute part number. Additionally, neither dealer could locate a GM replacement mirror that matched the design of this vehicle's rear view mirror. The replacement mirror that was specified in the GM system only has ONE connector (of a different configuration) and is approximately $493.00!!

Who knows how much re-wiring is involved with replacing this mirror and installing a new connector that ties back to the harness, headlight control module, Body Control Module... The light sensor on this vehicle is part of the mirror. Most other GM vehicles I have seen have a light sensor mounted somewhere on the top of the dash.

I have now tried to slightly adjust the pin on the mirror (that connects to the orange wire) in an attempt to keep a tighter connection. We'll see if it works.