1987 Audi 5000 Radiator Fan Problem

It is hot here in California and I am tryng to fix my 1987 Audi 5000 Radiator Fan Problem:
A. It only works with either the airconditioner or heater turned on.
I am looking to find the various relays and thermoswitches, but my Factory Benley Manual is of not of much help.
Does any know what publication might be helpful to update, what appears to be a rather complicated problem.
I am thinking of just wiring the Radiator Fan, so that I can just turn it on from the dashboard should temparatures rise too high.
martino-
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Wiring direct is possible but fixing it correctly is rather straight forward.
The fan operates at three speeds controlled by a resistor pack located on the frame under the radiator. This resistor pack is not likely to be the problem.
Fan speed one operates when the AC compressor is on which is the case when the heater is in the Auto mode.
Fan speeds two and three are controlled by a thermoswitch located just under the lower radiator hose on the back of the radiator. The is a common failure and easily replaced. Cost is usually about $20.
Alternatively, the relays for fan speed one and two are located in the main relay box under the hood and just in front of the windshield on the drivers side. The relay for fan speed three is in the auxiliary relay panel under the dash by the drivers left knee. It is a large double wide relay / controller that is difficult to remove and replace. The relays for speeds two and three are not likely to both have gone bad but it is possible.
There is a fusible link just under the brake master cylinder that provides the ground connection for all three speeds but if speed one is working this is not the problem.
My guess is that the thermoswitch on the radiator is the problem. You can remove the plug and short the contacts to test if the fan comes on but be very careful if you try this because the van is close to the switch and wires.
TonyJ
martino wrote:

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wrote:

Thanks Tony!
I'll work on this over the weekend...
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