Hi all, I did some searching but need some more advice. I have an 87 RS, recent L31 carb set up.

Previous owner installed a manual radiator fan switch and I'd like to move back to an automatic switch. I bought a temp sensor with build-in 195* switch and would like to know how to wire it up. It only has one electrical connection on top.

Currently, the manual switch taps into the fan + and a constant 12v near the relay. How would I go about wiring the automatic switch in? Which wire goes to the automatic temp switch?

Thank you for the help.

 

You use the switch to ground the relay that turns on the fans.

I am having a hard time visioning what was done to install the manual switch, did they cut anything?

 

This will get you where you want to be.

 

Perfect, exactly what I needed. Thanks guys.

They didn't technically cut anything, just tapped into the existing wires to bridge power directly to the fan via a switch. Right now the manual switch connects the fan directly to the 20A battery feed. A simple on/off switch - one goes to the fan, the other goes to constant power. Even with my car off/keys out I can turn the fan on.

My guess is they were having trouble with the stock sender or relay? I'll go through everything and figure it out. The ground connection to the sensor was what I needed. Thanks again.

 

I have a similar problem and want to do the same. The only difference is that I found a blue wire from the manual switch to the cooling fan relay (green in my car and black on the picture above). Can I disconnect the blue wire from manual switch and transfer to the coolant fan switch/sensor? As I read in the service manual, it should work, but I am no electrician... Nothing seems that has been cut off. Thanks!

 

Yes that should work.

Fan switch actually goes in the pass side head, in the same hole that midias' drawing shows, just, the other head. The thing on the driver's side is the temp gauge sending unit, don't want to do away with that.

 

Super thanks! I did find the cooling fan switch in the engine and its broken. I think that may be the reason why the previous owner replaced it with a manual switch. Now, I grounded the cooling fan switch wire, and it seems that there is current( my light came on on , but the fan did not come on. Is the fan suppose to come on? The fan turn on with the A/C on and the manual switch.

Also I have irocz 1986 LG4, and i thought i was suppose to have a fan relay in the driver side, close to the brake booster which I found it, and that is where the manual switch is connected to. But i see another relay in the front passenger side close to the headlight which have wires to the fan. My car currently have a single fan.