Both backup lights went out at the same time. Bulbs and fuse check good. I've been told of another fuse panel under the hood but I don't seem t have one. I've seen pictures but my Jimmy doesn't match the photos. (??) I don't know if the relays located in glove box have anything to do with it or not. Any help is greatly appreciated.

I'd have to say look at the trans switch that turns it on in reverse on the side where the cable goes into that black connector - it can be adjusted.

I see what your talking about. I'm not clear on how to adjust it.
GM