I second what Ramfan said. Look under the dash on the passenger's floorboard. Just to the left (DS) of the fan there's a 4 prong plug(light blue with a yellow tracer, tan w/black tracer etc...). The plugs go bad, and plugs directly into the resistor which is held in by two 7mm screws (I think).
If someones been kickin' the plug it doesn't help. I've seen 'em go bad and give a bad contact= irregular current = does what it wants.