924Board.org

[gml]

Onto fixing the next issue, which is that the right side (drivers) cooling fan does not seem to run under any circumstance on my 1982 924 NA.

The left side cooling fan runs in full power:
- when the A/C is turned on, and/or
- when I jump the thermoswitch connectors and turn on the ignition

Fan motor works: both fans turn on when I connected the fan pins directly to the car battery. The driver side fan seemed to be a little bit rough, but it was running with direct power.

Cooling fan relay works: pins A-B and 30-87 have infinite resistance, and when I connect the car battery directly to pins 85-86, I hear a click, then pins A-B has 0 resistance, and 30-87 has 0 resistance. (Testing procedure at Clark's Garage)

Fuse replaced: fuse 3 on the additional fuse panel has been replaced with one that had continuity, though the old fuse seemed okay.

Cooling fan resistor seems good: I removed the dashboard instrument cluster and found a ceramic circle with two wires/pins behind the tachometer. Unplugged both wires and tested continuity from one pin to the other, it was reading about 3-10 ohms.

Current thoughts:

- Clark's Garage says that the resistance should be less than 1 ohm. Is it possible this is my issue? Perhaps the driver side fan motor, which probably hasn't rotated in years, needs a bit less resistance to kick into operation? Is it a good idea to test skipping the resistor by jumping the connectors to those two pins on the resistor?

- Is there another resistor I need to test? Clark's Garage says "is highly unlikely for both fan resistors to go bad at the same time" but that could either be a 944 thing or just a typo.

- Given what I've tested I am concerned there's an issue somewhere along the line with the wiring. Any general tips for chasing down wiring issues (testing procedures or steps to follow)?
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George

1982 924 NA 5-speed

[jacobroufa]

That sounds like wiring to me based on the rest of your diagnostics checking out as they have... I would check continuity of the wires for the driver's side fan to the relay and ground.

That said, I don't have an answer as to your resistance question..
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1980 Porsche 931
1981 Porsche 924 Weissach

[gml]

Finally figured it out!

The connection between the push-in electrical connector and the two pins on the fan motor is somehow failing. It works even if I connect wires directly from the push-in connector to the fan motor pins. There's really bad clearance for that push-in connector so maybe its just not making good contact with the one pin. I sprayed it with electrical cleaner but I can't really clean inside the female connections on the push-in connector so I am not sure what else I can do. Meanwhile the bridged pins work great so I am inclined to move forward with that approach.

Any recommendations for a clean way to bridge this connection? The push-in connector works and the fan motor pins work, but they can't be connected with each other. So I don't want slice anything apart, I would just like to make a bridge with decent weatherproofing, something that'll be good enough for a few years and allow me to save the original setup later down the line if there's a chance to refurbish the radiator assembly.

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As a first timer I'm feeling pretty pleased I was able to diagnose the issue. For any other newbies who are curious, I had the positive battery terminal hooked up, and the negative battery terminal wired to a test light.

Looking at the wiring diagram (WSM Vol 4, Sec 97, Part II has the cooling fan wiring), I used the test light to see if I was getting voltage in the following locations in order:
- Fuse 3 on the additional panel: all metal contacts on the fuse and the fuse holder should light up
- The two pins on the fan resistor behind the tach: both pins light up, so I'm getting voltage into and out of the resistor
- Note: at this point the wiring diagram demonstrates that the fan relay only affects fast fan running speed. The driver side fan was never running, even with the thermoswitch jumped, so the fan relay was a useless thing to test. Only finally understood this wiring diagram once I was testing it out on the car!
- The fan motor push-in connector: unplug it from the fan pins and you should see one of the female connections on the push-in connector light up.

At the last step I was surprised to see that there was theoretically supposed to be voltage coming to the fan. I connected one wire (one end female spade, other end male spade) from the fan pin to the push-in connector, then touched a wire from negative post on battery to the other pin on the fan motor. The fan started running.

Then I jumped the thermoswitch, and did the same jump from the vacant slot in the push-in connector to the fan pin. This also worked! This demonstrates how the fan is supposed to run — with the thermoswitch active (engine hot) the driver side fan should run as long as the battery is connected, even with the ignition off (since the wiring circuit starts from 30).
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George

1982 924 NA 5-speed

[Fasteddie313]

Use some pointy pliers or a small screwdriver and bend the metal female terminals more closed so they fit tighter into the male ones..
They are probably just stretched out from time and vibration..

You can also completely depin the connector, take the pins right out of the plastic, and then work on them..

Another possibility is that the pins are pushed back in the connector.. Check for that.
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80 Turbo - Slightly Modified