early e30 electric fan wiring

[_Keith_]

That black wire should not be used if your using the high temp sensor line.

[E36M3LX]

I have about the same setup. Just unhook the small overflow hose at the top of the radiator and lift the expansion tank up. And I'll squeeze the hoses to move any air around once or twice.

thanks for this info! i was thinking about trying this so thanks for clarifying

[E36M3LX]

That black wire should not be used if your using the high temp sensor line.

gotcha, i will disconnect the black wire and check the fuses

[E36M3LX]

update!

got the fan running! i had everything wired right except that black wire you guys told me about. i snipped it and capped it. the brand new temp sensor is not working though, so i will be replacing with another.

i bled the cooling system a little bit by disconnecting the little overflow hose on the top of the radiator and that helped a lot! the temp sensor was finally getting too hot to touch but still wouldn't trigger the fan. so i disconnected the two wires that go to the temp sensor and touched them together and the fan turned on.

also, i had no blown fuses because the temp sensor never triggered the fan.

hopefully this helps future r3vers and thanks again for everyones help! i wouldn't have been able to get through this without you guys.

[_Keith_]

Good to hear


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[E36M3LX]

sorry to bump this thread but i need some help again. we ordered a new fan switch and it doesnt work either. we ordered the same one as last time and id like to order another one but a different one. what temp sensor do you guys use? id like to run a low temp fan switch

[pandaboo911]

Test it in hot water to make sure it's actually dead.

Low temp fan switches are pointless. Anything below 90C will make your motor run less efficiently and make less power.

[E36M3LX]

Test it in hot water to make sure it's actually dead.

Low temp fan switches are pointless. Anything below 90C will make your motor run less efficiently and make less power.

i would agree with your "low temp fan switch is pointless" statement IF i had an all oem cooling system, but this car is running only an electric fan with no mechanical fan. ive had experiences with our cars overheating when cruising up canyon roads at low speed, high rpm and hot summer days. ill sacrifice a tiny bit of HP if it gives my cooling system a head start. i use stock fan switches in the daily drivers but not this e30 swap that doesn't even have a mechanical fan.

i made sure the temp sensor was too hot to touch while in the radiator and it never turned the fan on, temps just kept climbing. but if you could explain how to test it in hot water, thatd be appreciated. i find it hard to believe that two brand new fan switches are faulty.

[RainRider]

i would agree with your "low temp fan switch is pointless" statement IF i had an all oem cooling system, but this car is running only an electric fan with no mechanical fan. ive had experiences with our cars overheating when cruising up canyon roads at low speed, high rpm and hot summer days. ill sacrifice a tiny bit of HP if it gives my cooling system a head start. i use stock fan switches in the daily drivers but not this e30 swap that doesn't even have a mechanical fan.

i made sure the temp sensor was too hot to touch while in the radiator and it never turned the fan on, temps just kept climbing. but if you could explain how to test it in hot water, thatd be appreciated. i find it hard to believe that two brand new fan switches are faulty.

Boil a pot of water and dangle the sensor with a couple of leads connected to an ohm meter. I did that and confirmed the temp switch worked. Still have not actually seen it turn on the fan. I think my radiator may be too efficient or I have no pateince. It must be working because I can see when the temp goes down.

[brahbarian]

Subbed will be doing this on mine soon