Maybe someone can help me with this is issue. Car is 89 Iroc 350 tpi dual fans. The problems is both fans turn on at approx 125 deg every time, and never turn off till car is shut off. I have a hypertech 160 fan switch and 160 thermostat. The only thing I can think of is possible relay going bad and causing to turn on earleir if that's even possible? It seems to correlate with after I deleted my ac and installed a ac delete box, but not 100% sure if it was happening before since I rarely drive the car. It also has a hard time going into open loop mode since it never stays warm enough to leave closed loop. If anybody has any ideas of where to start looking let me know. I've fixed both of my third gens with fans not turning on but this has me scratching my head.

 

Anyone.........?

 

 

I will have to give that a try, but isn't only the primary fan run off the fan switch? The secondary fan should be ran by either the ecm and temp switch iirc. have some spare fan switches laying around somewhere so if that's it that would be great

 

You've got it backwards. The primary fan (driver side) is run by the ECM. The secondary fan (passenger side) runs off the fan switch.

 

You are correct after looking at diagrams for awhile would not having ac pressure switch not hooked up to anything be causing this problem?

 

The 89 f-body tpi has the ac switch selected as normally open . If this had a normally closed setting say a memcal from a 86-88 tpi the fans would run all the time. the secondary over ride hypertech switch you have installed in the passengers head the tun on is really low. I believe you ment to state in your first post the car never goes into closed loop. There would be no issue with entering and staying in closed loop.

 

I'll have to check my tune I have a custom burned prom but im pretty sure its an 89 bin

 

Well I got it all fixed today I had a bad CTS and a bad fan switch why they were both turning on at the exact same time is still a mystery, but everything is working correctly now.