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Re: Replacing Cooling Fan Resistor Wiring

Posted: Sat Aug 30, 2025 5:30 am
by Darwin
Schrockahasi wrote: Fri Aug 29, 2025 1:58 pm Follow up question. When you removed the connectors at the fuse box did you have to loosen the box, pull it up and do it from the engine bay side or from underneath the dash. Access is cluttered under the dash.
Also how do the old terminals come out? Do you have to put a thin flat screw driver blade or terminal remove to get it out or did you have another method?
I guess the 12 awg wire is best. I did some Ai checking and it calculated 14 awg high temp for 25 amp fuse but I’ll go with 12.
I’m actually surprised rennbay or Lindsay hasn’t made kits for this as common as it is.
I chose 12 as I knew it would be sufficient for the current draw and the difference between 12 and 14 is minimal. It’s 4 wires so OD isn’t an issue.

I removed he central electrics box and had to swoon the connector. The original will have a prob on one side but I couldnt find an exact match. The ones I ended up using had two prongs.

You just need a removal tool to depress the prong to get the original connectors out. A small enough screw driver would be sufficient.

Re: Replacing Cooling Fan Resistor Wiring

Posted: Mon Sep 08, 2025 5:37 pm
by j1nx3d
Just sharing this as a curiosity and for posterity.

Checking the condition of my cooling fan resistor wiring was on my to-do list for a while. I quickly realised that it wasn't where I thought it was supposed to be for a '86 944. I eventually found an old post that on a late dash RHD 944 they are located in the drivers footwell next to the steering column, which was where I found it in a bracket, facing down.

There was a few things I noted that differs from what I read of most LHD (US) 944 experiences.

1. My car was delivered with no A/C so I only have one radiator fan. I therefore only have one resistor.

2. My wiring is in very good condition which I think may be from being inside the cabin and not exposed to engine heat or battery gases.

Due to it being a late dash RHD car the battery is mounted in the rear and Porsche vented it. I wonder if they vented the front mounted batteries whether the cooling fan relay wiring and battery trays would corrode how they are prone to..? They do have a big gap between the windscreen and the hood to vent.

Re: Replacing Cooling Fan Resistor Wiring

Posted: Fri Sep 12, 2025 7:46 am
by AZMI951
I will start by saying I’m good friends with Darwin and also that I work for an industrial harness manufacturer as an engineer. I have toyed with building the harness Darwin describes if there is interest since most cars need this by now. If you have interest I can build these. I have all the professional grade crimp tools to do it.

Re: Replacing Cooling Fan Resistor Wiring

Posted: Sat Apr 18, 2026 12:23 pm
by low944
I have just run into this same issue and my wires are bad all the way to the fuse box. I pulled up the fuse box and can see the wires crumbling.

Is this new relay an option yet?

I could use new pins for the end going into the fuse box plug if anyone knows what they are?

Thanks for any input

Re: Replacing Cooling Fan Resistor Wiring

Posted: Tue Apr 21, 2026 10:31 am
by Petethepug
Wholly …. Yea, but it’s a dry heat though. I looked at the injector harness on my Corrado g60 and mumbled, yea, that’s probably why they have an after run fan until the engine compartment cools. Now I know

Re: Replacing Cooling Fan Resistor Wiring

Posted: Thu Apr 23, 2026 3:07 pm
by shft22
In my case someone had cut off the resistor wires about an inch out of the "main harness." As I started to undo the harness with the idea of soldering in and extending the wires, I noticed that these wires' insulation was there but would come apart the minute I touched them.

Very carefully, I removed more harness wrap and inserted a heat shrink tube for each of these wires, then wrapped the harness back on. My concept is that the wire insulation has been kept in place by the main harness wrap, so as long as it's in place, the wire insulation should not come off even if it is brittle. I then soldered in longer wires, and so far it is working.

Eventually, if and when I remove the dash, I will replace the wires all the way to the fuse box, but for now the fans are working as they should.