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Re: 5ktq Radiator Fan only works on high...

Bernard wrote:

>My '88 5ktq's radiator fan only runs at its high speed.  The fan comes on
>when the engine coolant temperature reaches a certain temperature, and
>cycles on and off.
>Given the above behavior, is the resistor plate definitely bad?  How is the
>multifunction switch involved with the radiator fan?  Are relays suspect in
>any way?
>In short, how best do I figure out what is broken, so that I only replace or
>fix what I need to?

I have a similar problem with my '88 100t(euro). I have though speed 1 during afterrun cooling or AC on.
I browsed the wiring diagrams i Bentley, and concluded that if speed 1 is running OK, speed 2 can't be missing due a bad resistor pack, as the current for speed 1 has to pass both resistors in the pack.
I pulled the connector on the 3-pin termoswitch located in the radiator to do some testing. 

Ignition on, and
a) - short outer connector pins, this should start the fan i speed 3
b) - short middle connector pin and the outer pin with +12V, this should start the fan in speed 2.

I my case both speed 2 and speed 3 worked OK, so I am going to replace my radiator termoswitch. 

Hope this helps.
Be carefull with your fingers if you do this test....

Best regards
Flemming Christensen