924Board.org

[autobahnkid]

I just revived the A/C system on my 1980 924. It cools well for a couple of minutes and then stops. 134a Freon.
We have determined the passenger fan is not starting when the A/C is on.
The fan works when current is applied directly.
There is ground but no Voltage at the plug.
A/C relay is new.
Fuse #5is good.

What should I test?
_________________
1980 924 N/A "the beast'

[jason c]

Power & wiring in & out of the relay.
Do you have power to the relay?
Is the wire from the relay to the fan good?
Ground at the relay?
Power from the switch to the relay?

[autobahnkid]

I pulled the relay for testing.
When applying +12V to pin 85 and - to pin 86 I get no clicking. As per Clarkes Garage procedure. So I'm presuming relay is bad. How can I jump the wires to get the fan started?
Should I bridge A to B and 30 to 87?
_________________
1980 924 N/A "the beast'

[jason c]

[autobahnkid]

I went ahead and pulled the drivers fan relay. It is the same number and has the same pin numbers.

I tested that one and got nothing. I seriously doubt that both relays would go bad at the same time.
I numbered them and now will install as a swap and see if anything changes.

Looking at the wire loom behind the relay/main fuse box I see a thick red/black wire with a sheated connector that is not hooked up to anything
There is an empty pin close to where it is. I will try to take a picture.
_________________
1980 924 N/A "the beast'

[ideola]

Follow the troubleshooting instructions on this page under the section titled "Early 944s With Air Conditioning". It is identical to the first gen 924 troubleshooting regimen.

The only thing that is missing from that guide is the fact that there can be a wiring fault between the relay and the fan, which is not included in the regimen.

I mention this because I've had three separate instances on three separate cars where the main loom that carries current to the fans developed a fault in the wiring. One was at the fan plug, and the other two were both in the vicinity of the little clips tacked to the sheet metal that are used to secure the loom to the chassis. Strongly suggest checking the entire length of wiring. If you see cracks in the exterior plasticky sheathing in which the loom is secured, there's a good chance the wires themselves are also brittle, with breaks in the insulation and corrosion on the wire. Those kinds of faults can be intermittent and difficult to trace. Careful visual inspection is the best diagnostic.
_________________
erstwhile owner of just about every 924 variant ever made