I just bought a '91 Z28 with the dual rad fans, but a previous owner bypassed the ECM and fan switch, so they're hooked up to a toggle switch. Well, I really would like to return the duty to the stock configuration or if I could, hook them both up to the ECM.
a) Why did GM make them so one is turned on by the ECM and the other by the pass side head fan switch? Why not just let the ECM turn them both on?
b) Are there any drawbacks to letting the ECM control both?

This might be more for the DIY-PROM section, but is it possible to have have both fans controlled (at different temps), or is our wiring harness not set up for it? I see in the AUJP.bin with the $8d that there is a provision for separate turnon temps for each fan.

Closest thing I found was this.
https://www.thirdgen.org/techbb2/sho...&highlight=fan

 

Well, I think I finally found it. Looks like it's been explored before. https://www.thirdgen.org/techbb2/sho...&highlight=fan