Radiator Fan Issues

[lagz33]

Hi all
Have been having issues with overheating/1st fan speed not kicking in

Have replaced the following;
Coolant Temp Sensor
Thermostat
Expansion bottle+cap

Up until today the fans 2nd speed was kicking in but temps were getting up to 2/3 notches over 90.

My mechanic today changed the thermostat and found leaks on main and aux rad.
He also found that the connector and loom for the main fan had been bodged/repaired.
The original connector seems to be missing and someone has rewired it on with individual spade connectors rather than a proper connector block.

He put everything back together, but said my fan loom/connector is the problem...

Now the fan does not kick in at all, have to currently have air con switched on constantly.

Is the problem with the fan connector or do I need to address something else for example a relay?


Any help would be much appreciated, I dont have a clue what to do.

[lagz33]

Anyone?

[Carles20vt]

Wheel, I have temp problems with Coupe Quattro of my brother (Now I have a open post here) and past with my S2 so...

The best way to test fan circuit is disconnect principal radiator (bottom), and make a short circuit between pines. I don't remember what pin do but one is sender signal (one side), other first run (middle) and the last second run (Other side).

If starts first and second fan run, All circuit (Relays, fan, wires) are OK.

Check it and if it's ok, get out radiator sensor out and see if are dirty. It could be possible that radiator is dirty and need go to cleaner specialist.

See you,

[lagz33]

Will give this a go when I next get a chance, so busy with work :/

Thinking I will just remove the aux rad, for others it seems to work well

And most probably order a new main rad from quattro corner

[junkeravant]

On this side of the pond...

we also have problems with what you have. We in the States have found that the Connector between the fan wiring loom & fan shorts out because the (-) wire heats up and melts the plastic. Take a good look there & if you see burnt/scorch marks in the connector body, you know your problem. We have installed a big azz fuse in the circuit of the (-) to stop it from happening after replacing the connector.

[lagz33]

Ok, so today we shorted the wires for the coolant temp switch.
Both first and second speed kick in. While we were there we put the old coolant temp switch on, still no fan cut in

I think next we are going to get hold of a connector block for back of fan.....

So im thinking either its that fan connector block or two faulty coolant temp switches in a row......
Any ideas?

[andyg plym]

if it comes to it i have 3 spare fan motors with cowling

[lagz33]

Does that include the connector block/loom mate? Excuse my stupidity

[twoqu]

Surely if you are bridging between the terminals and both fans speeds work then that proves that the switch is getting 12V, and all the wiring/relays are ok as thats what operates the fan speed.
So that does point to the switch. You should be able to test the first stage switch with a saucepan, some boiling water and a multimeter as it switches on at 95C and off at 84C. Look for continuity between the supply and the first stage. The second switches at 102C which I doubt you can measure in the kitchen!