I have a 99 Blazer. A couple months ago I noticed that my reverse lights weren't working. Checked the bulbs, they're good. Checked the fuses, also good. Checked voltage at the sockets, nothing. I replaced the switch on the left of the trans. Still no luck. Didn't have time to dig any further. Tonight I went to put down the right rear passenger window. The lights came on. So I fooled around with it. The only way they work is when you push the button to let the window down and only that window. With or without it in reverse. Any ideas?