Sometimes, over fill of freon will keep the fan on. (a switch on the
high side line turnsi it on as soon as the compressor starts.
Al Brase

Bruce Nadig wrote:

> Howdy From Texas,
>
> I've been off the list since mid-December - out of town and away from
> e-mail. I've missed ya'll. It is good to be back.
>
> I have an unusual problems on my '87 GL. The "radiator" fan will turn on
> when triggered by the thermo switch or the a/c, as it should. However,
> once
> it comes on - and it has always come on in the high speed mode - it stays
> on, no matter what. It will stay on until the there is no more power
> available. It will run long after the ignition has been turned off.
> The fan
> runs until it drains the battery or until the battery is disconnected.
>
> As some background, the van did sit undriven for about 16 months while
> I was
> doing an engine conversion to an '87 Porsche 911 Carrera 3.2 liter
> engine.
> The radiator and its thermo switch are no longer a factor. Instead I
> have an
> oil cooler with a thermo switch that behaves as the radiator thermo
> switch
> does (except it is on/off instead of off/low/high).
>
> The thermo switch shouldn't be the problem as I have started the fan
> using a
> jumper wire with the thermo switch disconnected. Once the jumper is
> removed
> the fan remains on high. When the A/C is switched on, the fan will
> also be
> switched on and will remain on until the power is disconnected.
>
> Without having investigated very far, I am guessing that there may be a
> problem with the control unit that powers the fan on and off. I assume
> that
> this control unit is a simple relay, but I'm not sure. The Bentley manual
> isn't specific. Where is this control unit/relay located? Is it behind
> the
> panel at the left rear of the van?
>
> Any and all help is greatly appreciated.
>
> Cheers,
> Bruce
> motorbruce@hotmail.com
>