4crawler has an excellent write up on how to diagnose the problem here: 4Crawler

Start with the basics...fuses, lock switch, etc. Mine was a bad ground (85 4runner).

Good luck
Erik <img src="/forums/images/graemlins/cheers.gif" alt="" />

Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did.

85 4Runner, New motor, Dual cases, 4.88's, ARB's (F/R), 4" lift, 33's, Warn M8000#.