89 chevy truck power window and lock problems, (HELP)

I have a 89 chevy 4x4 truck the power windows and locks work sometimes,, the all the buttons work when they have power but its weird ,, sometimes the work and sometimes they dont,,, the other day i hit the brakes they stated working and then cut the truck off ,,, now not working again,, checked the switchs and when the windows are working and all be buttons work fine,, must be loosing main fire but i cant figure it out,, could it be a ground,, anyone had this happen to them,,, anyone have a link to a wiring dia of the cab,,,,

ok guys found the problem,, where the wires go though the rubber gromet between the cab and door the ground wire was broke,,, 4 wires into one,, simply cut the ground and re grounded to the door,,bam works like new,, hope this helps someone in the future

Ayup, 20 years of door opening & slamming'll do the wire harnesses in. Sorry I didn't see your post earlier or I coulda helped you out sooner. An alternative would be to get one from a used parts place. Had to do that for my Cam. Good work!