Tiger03447

The other evening this wonderful device decided to immolate itself and the two plugs that go into it. I have recently had problems with the headlight switch circuitry, but I don’t believe the two circuits interact with each other. I did not have the ignition switch on but the battery was connected. I can repair the wiring damage and the plugs that go up to the relay, but the main question is Why? The engine was off and I was not actuating the AC switch to run both fans. I think there is a demon in this car. Thanks in advance for any help.

orig944

Contacts fried over time, stuck "partially closed", but not enough to turn the fan. Contact resistance in the relay builds up heat and eventually melts everything. Either fan relay contact could be responsible. Things like this are why people put in remote relays in the engine compartment for the fans (I need to do this for mine.) A better relay would be a money-maker for ftech9 to address.

Tiger03447

How does one go about removing this relay from under the dash? It appears to be attached from inside the AC housing. Looks like the DME will have to be pulled..not sure about the instrument cluster..probably have to be pulled to get to the harness for wire replacement. Thanks in advance about this.

tempest411

It's not inside the AC housing. It's attached to the right hand housing support (at the kick panel) as I recall. You should be able to get access to it once you remove the knee bolster below the glove box. I think you end up removing the glove box in doing that...don't really remember. I believe it's the same pt# as the primary fan relay on the laft-hand side relay/fuse panel.All in all, not a big deal to swap out.

orig944

I do like the simplicity of my early car, there is so much less to keep repaired. But.... I do envy the later car's relay location, and the better fuse protection of circuits. There are completely unfused circuits in the older cars.

Tiger03447

This double relay assembly is attached to the white plastic housing above the right knee. It’s way above the gas pedal. Two square white plastic plugs plug into this unit. I thought this was for the aux fan (Rt side). But I could be mistaken. Thanks

orig944

I stuck my head up under the dash (not easy to do as an old guy,) and can see the relay you are talking about. I have no idea on how to get to it to get it out. After a bit of research, I'm going to make an uneducated guess as to what this is. At the very end of the PET, there is a listing for 000 093 095 00 - Installation Set, Oil Level Warning System, which includes relay 944 617 150 00 , a double relay. The wires are small to the mystery relay, so we know it is not driving the fans. The oil warning light is a low-current system, so I don't know why the relay would burn up. That is my conclusion as to what it is for, and unfortunately it is not shown in the schematic. Also, the owner's manual disavows it's existence.

orig944

This thread indicates the relay is behind the gauge cluster. You might be able to get to it if you remove the cluster.

https://rennlist.com/forums/924-931-...oil-light.html

tempest411

For an early car? I think the double fan relay was on the late cars only. On my early cars one of the fan relays is just above the right-hand kick panel, and the other is with the other relays in the fuse/relay center on the left-hand side of the car.

orig944

One of the two relays in the right hand kick panel is a double wide relay.

Tiger03447

This is not a fan relay as I first thought. It is a double relay that runs the fog lights. The relay and wiring can be removed with a light pull. It is suspended by the relay cover. That cover is either on a friction pin or is screwed to the AC housing with a single screw. The. Wiring damage, upon further investigation is much more extensive than I first imagined/realized.

pfarah7

Sorry to hear about the harness my friend.

orig944

In your 83, the fog lights have a single NO relay (Fog Light Relay) and a single NC relay (Flasher Blocking Relay) in their circuit. There is no double relay in the circuit.

If you don't already know how to read the schematic for your car, I recommend starting here: http://www.e38.org/understanding%20e...20diagrams.pdf

Tiger03447

OK I guess I don’t know what I am talking about and I am an idiot. If this double relay is not in the fog light circuit, why did it immolate itself and the rest of the fog light harness if it is not in the circuit? I will provide you a part number for this relay. When I bought it from a Porsche dealer, the parts manager said, “Oh that’s the super rare fog light double relay”. I had just given him the part number to go by, asking if he had such a relay available. I had thought at the time it was a fan relay. What is a NO ( normally open?) and I presume a NC relay is (normally closed)? As you can already surmise , I am not an electronics guy. But I am learning. Thanks for your input.

orig944

With the part number we can look in the PET to help determine it's function.