I don't think cheese meant to use the TPS voltage, just the movement to activate a switch. Problem with this is having the fan run on cool days and cold nights at idle.
RB's idea sounds pretty good except for the same problem. Same with the GPS. The solution can't have anything to do with speed, motion or air flow, IMHO.
The orifice sounds interesting, but even with the explanation I don't completely understand if it will do what Glen needs to do, activate a fan in hot conditions when stopped. The in-duct temp sensor might be tardy in operating the fan and shutting it down. He could be doing 40 before the duct temps fell.
That's why he asked here because if it were easy, he'd have done it already.
I guess I'd install a horn button within reach and use the horn ring to run the fan. Not going to help the valet.
