If i wer you and I wanted to keep the fan on when i shut the truck off, i would just wire the fan controll straight to the battery then it would stay on untill the coolant temp went down, rather than to an ignition source that should shut it off wen you turn off the key. i kno thats how 95tacokid's set up is. I dont have the overheating problem though so i just wired mine into the radio. That way, i know if my radio isnt working, than neither is my fan haha (n____r rigged).