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E30 cooling fan

Discussion in 'E30 (1984-1993)' started by Grrrreat, May 15, 2008.

    Grrrreat guest

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    the High speed is not working on my cooling fan infront of the radiator. i have replaced the brass radiator temp sensor, and the little black Clutch (piece attached to fan, can't remember what it is called) to no avail. :confused: i have tested the fan and both speeds work when hooked directly to the battery. anyone know how to do the wiring so i can place a toggle switch somewhere inside the car?
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    By the "black piece attached to the fan", do you mean the resistor pack? If so this only is responsible for the low speed fan operation. High speed is the full 12V applied to the motor through a relay and fused circuit. The high speed fan only switches on when the temp switch in the radiator closes. The A/C system only switches on the fan in the low speed setting.

    How do you know it is not working properly? Are you overheating? Have you tried jumpering the wires at the temp switch to verify it will run in high speed when installed? It is possible that the relay for the high speed circuit is bad and since it is the same as the low speed relay you can swap them for a test.


    Grrrreat guest

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    thanks for the response.
    yes, that is correct. the resistor pack that controls the low speed.
    my car never overheats but does hit the middle of the temp guange when i run the a/c in bad stop and go traffic. i would like to use the high speed fan setting to keep it cool, hopefully helping my a/c stay cooler. i have switched the wires to make sure the high speed works but that was about a year and a half ago.
    the low speed no longer turns on when i run the a/c.
    It is getting hot again so i want to work on it.
    i am not familiar with the relays that work the fan speeds but I will look into it. thanks again for your response/insite.
    Matt G
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    cooling fan

    I am going to add to this topic the repair of my radiator fan motor on my 96 318ic. The motor is wired to run on two speeds. Low speed for A/C and high speed when the radiator gets too hot.

    Note that my fan has six blades and the resistor is located in the wireing harness prior to the motor. Its the silver cigar cliped to the the fan shroud (pic 1 and 2). After testing the wireing as described in my Bentley repair book, I found the resistor to be shorted out. So, I tried to get a used fan motor but found that to be $150 used. BMW sells the fan and shroud as one piece and for $400. Radio Shack had resisters and after testing a ten ohm, (too much), settled on a one ohm resistor. I finished the assembly by making a cigar type holder out of a piece of aluminum tubing and epoxyed the ends. The resistor cost $1.95, that with some clips, epoxy and scrap tubing and your in business.
    Pic #1 location on the fan motor showing the resistor.
    Pic #2 fan and shroud removed from engine bay
    Pic #3 shows my test wireing
    Pic #4 close up of new resistor.

    Hope this helps a few others...........Mike
    From our staff of Tech Service Advisors, thanks to Daniel Patzer for his assistance.

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