lack luster A/C at stops made me investigate the fan. Fan does not turn on with the A/C.
I have a good fuse and a good tested relay and the fan was jumpered and works, so its a matter now of what it is that is supposed to trigger that relay.

thanks

 

It's triggered either by the engine coolant sensor or the temp sensor on the receiver drier.
Try jumping the terminals on the receiver drier first.

 

On the earlier cars, the aux fan is triggered by coolant temp (radiator switch), ATF temp (torque converter switch), and refrigerant temp (switch on the tube at the receiver/dryer).

The refrigerant temp switch doesn't work too well. Take a look at this thread for some ideas. Read all of it.
http://forums.rennlist.com/rennforum...od-please.html
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I was testing MY '85 for this very reason last weekend. I too am not happy W/ how little the aux. fan activates W/ either radiator temp. or A/C.
I found one of Wally's troubleshooting guides on http://nichols.nu/tip163.htm and found that everything on my car checked out but fan is still "lazy"
I am also interested to see if the fan can be more "active" esp. since summer is here.

 

The fan will also come on at a reduced speed if the intake is too hot, even when the car is off. The intake sensor has 12V all the time. The round ceramic resistor is on the passenger side, in front of the radiator, and is fed by it's own relay, separate from the regular fan relay.



Here are the VW part numbers for the radiator sensor, if you want it to come on earlier. These switches are only ~$12.

823 959 481 | 75-70C | 167-158F
823 959 481D | 82-77C | 180-171F
823 959 481F | 92-87C | 198-188F (stock)



To easily see if the radiator or A/C switch has tripped, check for ground at this odd wire near the jump post. (It's where the towing-pkg-auto-trans-cooler-overtemp-switch-harness plugs in.) You could also wire your own sensor here. Ground to activate the fan relay.


thread

 

excellent info guy, I will get right on these and check them all. Im certain the dryer is not tripping this as it should.
I may just end up relaying my own deal with the A/C push button as suggessted

 

Turned out to be pressure switch. Since its the summer I just jumpered the pressure switch until I relay this for ac switch.

Thanks for the help