Radiator Fan Circuit Blowing Fuses

So when I bought the car couple years back I noticed that the radiator Fuse 1, was blown. Didn't really pay too much attention to it because I was going to be restoring the whole car and figured it was probably just a bad connection or something. So car now fully restored and running and guess what……yeah my radiator fan Fuse keeps blowing. Almost overheated while I was working on the car. fuse blowing has Happened twice now so I figured I have an unknown gremlin monkeying around in there.

I have brand new radiator fan. Connected to old coolant thermostat sensor. Could the sensor be going bad causing this? Or should I be looking at more of a wiring problem. Sensor and radiator both work fine when "working" ie when the fuse is not blown but obviously something isn't right or I wouldn't keep blowing fuses. Any pointers would be appreciated!

UPDATE: I just jumpered the battery to the fan separately and the fan only works when grounded and power supplies to the red/white wire. Is this the after run circuit? Also I assume fan should also work (possibly at lower speed) when grounded and power supplies to the red/black wire??

Make sure that your fan has a good ground to the Brown wire on it.

The Radiator Switch can go bad, but as it is a switch that closes or shorts when it gets hot, it is basically a thermo fuse.

The After run fan switch is mounted on the rear right corner of the valve cover, Looks like a big brass nut.  it has a single brown wire connected to it..

The Fuse in the Cabin is connected to a relay on 88-93 cars that is located on the fender of the car next to the battery. It is more likely that this 53 relay goes bad and is subject to water and battery gas corrosion.

On Older rabbits they didn't have all this and ran the fan straight to the Radiator Switch, then the fan.

Motors can go bad, when they get hot.  The fan circuit is in the back of the Bentley in the a/c section since I see that you have a 2 speed fan.

The fan fuse is 30 amp, and I have had that socket that holds it go bad and Melt, which can cause issues and the fuse blows due to heat and not really a short.



I decided that after I had replaced that fuse socket, I would replace the fuse with a 30Amp circuit breaker in it's place.

Also if you take the wire off the after-run switch, and ground it the radiator fan should run full time it is shorted.

Thanks for all the info Briano1234, this is exactly what I was needing! Will have a good read through all this and see what I can track down. The radiator fan connector (harness side) looks a bit like it was melted at one time, the outer shroud, the contact look pretty good though. Will check the relay and try to test the circuit. I was looking for that in my Bentley manual but couldn't find it. Will have another look to see if I can pin point this issue.

On the 30Amp fuse holder that you mentioned, that is actually my fuse box in the cabin. Are you saying that is what went bad on yours? How did you replace? I assume new fuse box? Will double check my fuse box but I seem to remember that, that particular fuse holder (slot on the fuse box) did look like it may have been roasty toasty at one time. Will double check as it's been a while since I had a good look at it.

No you don't need a new fuse panel, as the 30 amp fuse is usually located above it in the aux relay holders.

I used breakers in my A/C position which melted, and in my Radiator fan  as they open, then cool off and reset with no other intervention.

aux fuse above the main fuse panel


Circuit breaker, cut the legs off to fit.



The inside of a fuse box, notice that f1 on the right is corroded, so a good cleaning with Vinegar will remove that green sheen.