Aux. Cooling fan inop???

[pmkls2]

Okay, I have a '90 240sx and my aux cooling fan for the a/c wasnt working. I tested the wiring leads to the fan and found 12v on one wire and a good ground on the other. I had no clue as to what the other plug was for so I figured the motor was bad since I had power and ground. So I pulled the fan and disassembled the motor and found nothing wrong so I hooked up 12 volts and it worked. I got to looking at the wiring and found out that the problem was not the power feed but I assumed that there is some kind of switch that completes the circuit. Is this true ? I cut the 2 blue wires going to the one connector and soldered them together and the fan works fine now. So, what is wrong with the car ? Is there some type of switch that has gone bad somewhere ?

[pmkls2]

Okay, I have a little more info for ya. There are 2 connectors going to the fan okay. The first connector has +12v and ground. the +12v wire is blue and ground is black. The ground wire goes directly to the motor but the blue wire loops over to the second connector. On the second connector both wires are blue. The one wire comes from the first connector and the second wire goes out to the engine bay somewhere. Now this is my impression from looking at the wiring. Nissan over-complicated the system is all. From what I can draw from it looks like the relay sends power to the fan everytime the clutch is engaged,but there is a switch somewhere on the engine that completes the circuit. My guess is it is a thermal switch to keep the fan from running with the engine cold. All that I did was bypass this switch so that my fan would work. But I would like to know if I am right and where this switch is. Thanks,

Phil

[NISTECH]

yes it is either switched by the ecm,a/c pressure sensor or a temp sensor. not sure on your year dont have a service manual handy to be sure.

[Nismo_Freak]

90's have a temp sensor IIRC.

Would be nice if people could understand warming up a car before driving it... would simplify cars to some extent.