My tail, brake, high brake, backup & license plate lights all failed at the same time the other night. I searched this forum and all over the internet as to what the problem could be and could not find any discussion on this problem, so I took it to my mechanic as I did not have the time or skill to do the wiring tracing. I am posting this to help anyone else who may have the problem and save them a few bucks. The problem was a connector; GM Part # 15304995 which can be procured on line for about $35.00 (photo attached). Cost me $310.00 in labor tracing the wiring and $79.00 for the connector. After my mechanic found the problem he went to the local Chevy dealer to get the part and they told him this is a relatively common problem on Suburban's, Tahoe's, etc. of this era which is why they had this relatively obscure part in stock which can easily swapped out.

 

Find a new mechanic.