bendavis2

So, the passenger side fan in my 1983 Porsche 944 won't run.

I've worked through the write-up in Clarks Garage, and don't know where to go now:

Relay Testing
- Cooling fan relay has been tested and works as expected.
- A/C fan relay has been tested and works (though the clarks procedure called for me to jumper A and B, and there are no A or B spades on the AC relay.)
- Replaced fuses 3 and 5 with new fuses.

General Testing
- Jumpered the thermofan connectors and the driver side fan ran at slow speed.
- With Thermofan jumpered, and the ignition set to ON: ONLY the driver side fan runs at high speed. The passenger side does nothing.
- Wtih Thermofan jumpered, and the A/C switch turned on: ONLY the driver side fan runs at high speed. I checked the plug going to the passenger fan, and it had no current.
- Connected 12V battery directly to passenger fan, which ran great.

I suspect that though my relays are functioning properly, the wires running into the bracket that holds the relay may be in bad shape, or the wiring somewhere else in the system may be bad.

I'm looking for any ideas or suggestions from anyone who may have run into something like this in the past!

Thank for all your help or advice,

Ben Davis
Portland, OR
1983 N/A Porsche 944

V2Rocket

The wiring to the fans tends to get twisted and beat up over time with maintenance, you may just have a bad wire.

odonnell

If you end up needing a new motor, I have one laying around. It has a 6-blade fan mounted on it - you will need to trim the blades slightly so they clear the radiator hose to the water pump. It's not a very difficult mod. PM me if interested, I'm mostly looking for whatever it costs to ship plus a couple dollars for my time and patience at the post office.

John_AZ

Does the passenger fan run with the AC on?
J_AZ

bendavis2

The passenger fan does not run with the AC turned on. It doesn't run under any circumstances that I can create.

Ben
1983 N/A Porsche 944

odurandina

turn it. does it feel good and turn easily ?? if not, it's smoked.

if you can wait a few weeks i'll have two fans available.

william_b_noble

so, let me get this straight - the pass fan doesn't run no matter what you do, but you haven't tried applying 12VDC to the fan terminals? why don't you start there, if it doesn't run with power applied you can quit testing other stuff

V2Rocket

He said in the first post that it runs with 12v direct.

mhariush

Follow the clark's instructions on jumpering the fans, then wiggle the wires on the fan that doesn't run.

On mine there was an issue with the connector and it went on when I wiggled it. I ended up replacing the fan. But I'm sure it's possible to fix the plug...

william_b_noble

indeed - missed it, it was buried - so the way to troubleshoot is to check the circuit one step at a time. I'd start with the ground since it's fast to check and then follow the power backwards from the fan.

bendavis2

So after rigorous testing, I think there is a short somewhere along the wiring between the relay (which is working great) and the passenger fan (which also works with 12v direct.)

I'm not really prepared to cut open the wiring bundle and try to find the short.

Does anyone know if the fuse can handle both fans running on the same circuit if I just splice the passenger fan power on to the driver side fan wiring?