Replacing Cooling Fan Resistor Wiring

[breilly951]

Hello all, I need some assistance with my 86 951. The wiring to the two 0.9ohm cooling fan resistors has completely deteriorated and needs to be replaced. Does anyone know what the correct gauge of wire I will need to replace it. Also does anyone know a vendor who carries wires with the factory color codes. Many thanks, Bruce

[Thom]

You could choose to shorten the wires to delete the resistors, in which case the fans would run always in high speed rather than both low and high speed.

[Tom]

Hi and welcome to Carpokes!! The original wires are 2.5mm^2. The closest commonly available wire in the US is AWG 12 gauge, which is slightly bigger. AWG 14 is slightly smaller, but closer to the metric size, so you'll see that listed on a lot of charts as the closest 2.5mm^2 wire. I'd err on over-sized (AWG 12) given the current those wires flow. The original colors are: red/green and black/red; and red/white and red/black. Finding that wire in those colors might be tough. You can order it, but it's cost-prohibitive at most places. See for example:

https://www.pacergroup.net/12-gauge-str ... rine-wire/

If you hunt around, you may get lucky and find more affordable wires in these colors -- or maybe harvest some from a european junked car. What I sometimes do is take a solid-colored wire with no stripe, and put small segments of shrink tubing on it in the stripe color. It does not look stock, but it maintains the factory color coding for the future.

[breilly951]

Tom, thanks for the welcome and I look forward to participating on the site. Appreciate the info on the wire gauge and going with the larger size makes sense. I will see if I get lucky finding some factory colors but the shrink wrap idea is a great solution.

Thom, thanks for thoughts on the delete but I will try the wire replacement first.

Many thanks to both of you.

Bruce

[Darwin]

Tom, thanks for the welcome and I look forward to participating on the site. Appreciate the info on the wire gauge and going with the larger size makes sense. I will see if I get lucky finding some factory colors but the shrink wrap idea is a great solution.

Thom, thanks for thoughts on the delete but I will try the wire replacement first.

Many thanks to both of you.

Bruce

I usually buy all my wire from this place. They can do pretty much any color combination, and lengths down to 5'.

https://4rcustomswire.com/

[breilly951]

Thanks Darwin!

[Tom]

I looked there and didn't see any 12 gauge with stripes, but maybe worth a call. I also tried to pull up Eagle Day, which used to have a lot of hard-to-find electronics for our cars, but was bummed to see their domain no longer is active. I guess they went under. I also saw this little tool, which immediately made me want to create and 3D print my own.

[breilly951]

Tom, very cool tool. Knowing the wire size needed, I did some searching for classic wiring last night and found this source with several options to choose from: "Rhode Island Wiring Service, Inc" (WWW.riwire.com).

[944TurboS]

Getting back to these resistor wires, mine were deteriorated right to the boot so probably need to run new wires.

However, where do they run to and how do I get to them from the interior?

I am hoping somewhere close is good wire I can solder a new wire in to prevent having to go all the way to the fuse box as someone suggested.

[Tom]

If you can trim them back under the hood and solder on new wires, sealed with adhesive lined heat shrink, your life will be easier. Those wires end up going to a gang plug under the fuse box. It is possible to replace the whole length of wire, but you either need to pull up the fuse box (which puts old brittle wiring at risk) or work on your back with the driver seat removed (which puts old brittle backs at risk). Lots of current, so be sure to use wires of equal of bigger gauge.