Evaporator resistors, need some help or suggestions

[whynotvw]

I haven't posted anything for a long time, but I need some help.

My 1987 weekender a/c fan only works on 12 and 4. #3 does not work. I checked the D pillar 50 amp fuse and that was good. So I'm guessing it most likely is the evaporator resistors. Unfortunately NLA. So I'm trying to find some used ones or maybe there is other alternatives out there.


I just did the front heater box and installed and did a Jeep resistor mod. Can other resistors work?


I did the search on this subject but any other help would be appreciated. If you know anyone with the original parts or other alternatives that would work that would be great.

Any help would be appreciated

[Farf]

If I remember correctly, speed 3 is energized through the a/c relay then on to the resistor bank. Speeds 1 and 2 have to go through the resistor bank including the 3rd speed resistor. Take a look at the a/c relay, see if it energizes when you power up 3rd speed. Speed 4 bypasses the residtors.

[pablum]

EDIT: self-censor by the guy confusing horses head for its ass.
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The wise man learns from history, the fool from experience.
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I see [a cat] in the street and i aim for the pest with my car. -- bluebus86

[Howesight]

I agree with Farf that your problem might be a relay and not the resistor. The reason is that there are two blower fans and two resistors in the AC cabinet. The likelihood that both resistors would fail at once is low, and I therefore would suspect the relay.

See the June 17, 2016 post by Farf in the link below which contains his annotated wiring diagram. I believe that your problem is to be found in the AC relay at terminal 6/4. That relay may have failed. You can check this by jumpering between terminal 8/2 (this is the 50 amp 12V supply)and terminal 6/4. If this makes your fans run, then the resistor(s) is not/are not the problem. Here's the link:

http://www.thesamba.com/vw/forum/viewtopic.php?t=3...p;start=20
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'86 Syncro Westy SVX

[Howesight]

To add a bit of useful detail to my earlier post:

1. Find the A/C relay in the D-Pillar space. It is the tall, double-height relay.
2. Remove the relay and look at the wiring diagram on the side of the relay.
3. Using some stripped copper wire (2.5 mm), make a short jumper wire and wrap one end around the 6/4 pin on the bottom of the relay and the other end around the 8/2 pin on the bottom of the relay. Do this in a way that will permit you to re-insert the relay into its socket. Make sure that the jumper is not touching any other pins and use electrical tape or similar to ensure that.
4. Now, plug the relay back in and test the AC evaporator blower fans. If the fans run, the relay or the rotary switch on your dash is the problem. If they don't run, then the resistor(s) is/are the problem.

The point of the above is to connect the two terminals marked in yellow in the diagram below (thanks, Farf) which would be connected if the relay was working properly. This jumper sends 12v drawn from the 50 amp fusible link to the wires connected to the two resistors at the segment marked "3", meaning, 3rd speed of the 4 speeds. As you can see, the highest speed (4) is controlled by a separate relay (marked "evap. fan relay" in the diagram) that applies full 12v with no resistance to the two evaporator blower motors.

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'86 Syncro Westy SVX

[AtlasShrugged]

[whynotvw]

Thanks for the advice, I did exactly as you said, connecting the 8/2 and 6/4 and the fan switch on 3 worked so I'm so thankful for your help. I just ordered the a/c relay from Van-cafe.


I'm really glad that I didn't have to change the resistors.



thanks again. God Bless.

[Howesight]

You are quite welcome - - glad to help. Now post in the topic heading that the problem is solved.
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'86 Syncro Westy SVX