Howdy folks. Ive got an electrical gremlin on my 89 Sub that I hope some of you have seen before.

When I turn on my vent fan to the low or medium settings all is well. However when I turn the fan on to high my charging voltage drops down to about 10.5 to 11 volts. For some reason on the high setting it is pulling way to many volts.

I have tested the alternator with my voltmeter and it is pushing about 13.5 volts so that is ok. No other circuits, such as light, wipers, etc drain volts like the dash fan does on high. I can even put on about 300 watts of offroad lights and voltage barely drops.

I first went under the hood to check the relay on the heater/ A/C box and noticed that the positive wire ( from relay to fan motor) was very warm on the end near the relay. The relay itself was not warm at all. All of the grounds appear solid so all I can think to is replace the relay. I want to make sure I am curing the problem though. A bad ground could make this wire heat up right? Or, could it just be that the relay has gone bad.

I should add that on one occasion the fan shut down after about 30 minutes on high. I will turn back on after it rests a good while. Ive tested the blower motor on 12volts and it runs fine.

Open to all suggestions...Im sweatin' bullets in this heat