This has hapeened twice. The reverse lights on my blazer will come on and stay on until I remove the fuse for the power side mirrors (3 amp). It doesn't matter which drive the car is in P, R, N, D, etc.. Switching between them doesn't help. Turning off the car and remopving the key doesn't help. The only way to get the reverse lights off is to remove the fuse. When I put the fuse back in the lights remain off.

It seems I have a very selective short. Any ideas on how best to find source of the problem?