Rad Fan Wiring

erixon

New member
Hey guys,

So I am having somewhat of an issue with my rad fan. The guy who did the swap never hooked the fan up properly, he wired it to the ignition coil. I am somewhat unfamiliar to how its wired in, I have done all the work successful so far, just learning as I go along. Can someone tell me the process of wiring up the fan properly, so it kicks in when it is supposed to?
 

Pechin0351

New member
Well, on my 185, I delved deep into the fan wiring a little while back and found that you have a mass of garbage that kicks that fan on. There are 2 relays and a fuse to compete with in the fuse box, plus the sensor on the bottom of the radiator that controls the main fan relay, when the coolant is cold that sensor closes the loop which turns off the relay, when hot, the circuit on the sensor side opens, making the relay allow power to go to the fan... Some would say wiring a switch to the fan would make a novices life easier... I like the auto on shit myself... Happy to help with questions if I can
 

ulis_m86

New member
and you also have an ac sensor cut off switch somewhere by firewall passenger side make sure thats connected otherwise itll be an open in the circuit and keep the fan running constant.
 

dkpain

New member
where is this a/c sensor switch? i just removed the air conditioning in my 92 RC and the rad fans run constant as soon as the key is even turned to accessories on position.
 

Pechin0351

New member
If you look near where the AC lines went into the firewall, there should be a plug on your wiring harness that has (4 pins on mine which is USA wiring harness) that is what you need to jumper.
 

dkpain

New member
Found it. Thanks. luckily i still had the old hard lines. So i found the switch and put back in place. so now the fans are off. Since I'm racing the car, before the car heads out i pull the switch to turn on the fans full time. Really helps the temperatures.
 

FC Zach

Active member
This info has been extremely helpful, I've been trying to diagnose the issue with my fans getting constant power with ignition on for little over a month now. I never considered the AC pressure switch to be the culprit!
 
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