Have an '89 383 with dual factory fans. Primary fan works as it should from the ECM. Secondary fan motor tested and works, however, PO didn't have it connected to passenger head sensor. When engine was rebuilt and installed a month ago, we used a 180 deg temp switch and deleted the AC. I thought this fan was simply controlled by the temp the sensor was reading and that's it, beside going on if you had AC running I understand how the stock setup is supposed to work, but now am wondering if something is needed from the AC wiring to get it to kick on now?

 

You don't use a temperature sensor. You use a temperature switch.

 

Yes ok, my bad with the wording. I have installed a 180deg temp switch.

 

Not you ecm so disregard the ecm pin c9

 

Thanks TP for the help!

 

I think it might be d11 at your ecm it maybe a green wire or dark blue. I think the color in that circuit changed over the years.

 

The 88 Iroc I just bought had the AC compressor removed. The secondary fan relay was disconnected, but a short jumper was placed on the pressure swith and GND pins so that the secondary fan would constantly run starting from ACC ON. Not sure why this was done. have since removed the jumper and reconnected the relay with the understanding that the fan *should* come on in case of high temp. Is there any reason I should replace the short jumper so the fan constantly runs?

 

No, fans constantly running is an ignorant hack.

 

Painless has a wiring kit with relays and all for dual fan setup if your wiring is hacked up bad I recommend their setup.