I'm tired of a DOA or a malfunctioning switch in the right head. So, my plan is to use the hot to the driver side fan controlled by the ecu which will be set during the tune to power a relay to switch the ground to the pass side fan and have them both controlled by the ecm and turn on/off simultaneously. Yes? No? Am I hallucinating again?

 

It could work like that. The only problem I see is that electric fan motors draw a lot of power when they first start up, so it would be better to start them at different times. Personally, I like the stock switch in the passenser side head setup for the secondary.

 

Agreed but I must be cursed or something. My original Hypertech switch broke when I was doing the swap. The replacement was supposedly a 180* but turned on about 155*. I then tried a Jet. That one lasted about 8 hrs run time and is now DOA. And, I don't want to be sticking things in my radiator fins, so that's out.

 

155* or 180* is way too low, it will run all the time. On the other hand, the OE switch comes on WAY too high at 238*. Standard Motor Products (available at any auto parts store), has the following switches available:

on at 238* - part # TS147 (stock F body)
on at 211* - part # TS85 (Chevy Celebrity Iron Duke)
on at 204* - part # TS136 (89 TTA)

I think the TS85 is the best compromise, but the TS136 is also o.k.

 

Not with the 170* 'stat I have.

 

So, here's how I fixed the problem: