1st speed on radiator fan

[Ski]

BTW my air con also was numbered 214 so I swapped them around as a test.

[Slim m]

I cant see that their is anything wrong with the relay's, as i have moved them around and they all seem ok. But every time I put the fuse in for the first speed, the delay makes a clik noise and the fan comes on, even if the car is cold!!!!!!!!! Dose anyone know how the delay works?? Liam.

[dub007]

That should leave the coolant temp sensor to blame. Its in the bottom right of the RAD and has three wires going to it. I don’t know how you can test them, other then to replace it. And for that you need to drain the coolant, re add the coolant and open the two bleeder screws. I guess try unplugging it, then putting the fuse and relays back into place. It should keep the fan from coming on. Then you can take a piece of wire and jumper the plug for the sensor. Just try probing around with the wire between the three wires and if the fans come on properly when you add the jumper and shut off when you pull the wire, that should indicate that the sensor is bad. Don’t worry about messing anything up with the jumper wire, the worst that will happen is a blown fuse.

The moving of the relays to check was my first guess and it’s a freebie, but the sensor will cost more then a few bucks, don’t forget to add coolant onto the price as well. The clicking of the relays means that they are working. In my mind the sensor is the only thing left.

[Slim m]

That should leave the coolant temp sensor to blame. Its in the bottom right of the RAD and has three wires going to it. I don’t know how you can test them, other then to replace it. And for that you need to drain the coolant, re add the coolant and open the two bleeder screws. I guess try unplugging it, then putting the fuse and relays back into place. It should keep the fan from coming on. Then you can take a piece of wire and jumper the plug for the sensor. Just try probing around with the wire between the three wires and if the fans come on properly when you add the jumper and shut off when you pull the wire, that should indicate that the sensor is bad. Don’t worry about messing anything up with the jumper wire, the worst that will happen is a blown fuse.

The moving of the relays to check was my first guess and it’s a freebie, but the sensor will cost more then a few bucks, don’t forget to add coolant onto the price as well. The clicking of the relays means that they are working. In my mind the sensor is the only thing left.

Thanks for that!! I will try it and see what happens. Liam.

[Ski]

and should the relay work fine and no problem with temp sensor and 1st speed dosnt kick in, what else could cause such a problem?

[dub007]

Did you test the switch using a jumper? There really isn’t much more that would cause the fan to stay on. Maybe a small wiring issue but that is unlikely. The whole fan system is just some wire, the relays, thermal switch, resistor pack, and the cars computer plays a role as well. It’s fairly simple. The fact that the fan is stuck on is a plus. Finding out why a fan wont come on tends to be a larger challenge. Common problems with Audi’s pre 1996 are, resistor packs, relays and sensors. Having air trapped in the coolant pipes can also cause fan and temp issues.

[Ski]

sorry i meant if the fan stays off not on. Where can I locate the thermal switch and resistor pack? Maybe these are my problem.

[lagz33]

What sorted this problem for you in the end?
Ive replaced the coolant temp sensor and thermostat but 1st fan speed still not kicking in...