Hi

 

I can't remember when I last heard the radiator fan come on on my Felicia 1.3 GLI so decided to test it. Temp guage went up to red but the fan didn't cut in so I pulled the terminals out of the thermostat switch and bridged them and the fan came on fine. I put a new thermostat switch in the radiator but the fan still doesn't come on with the temp guage almost in the red.

I didn't top up the coolant after changing the switch because I only lost a tiny bit and it's still nearly on the max mark in the expansion tank but I'm wondering if I now have air in the system affecting the performance of the switch?

It also occured to me that the new switch may be defective, It's a Fuel Parts one I got on Ebay.

I suspect that the fan hasn't come on in a long while and as the temp guage doesn't often stray above the mid mark ( I drive conservatively ) I'm thinking that maybe I should just run wires back to the dash with a manual switch for peace of mind when I get stuck in traffic.

Any suggestions or observations would be appreciated as I'm a relative novice in such matters.

 

Alastair

sensor on the radiator ?

You ruled out wiring problems and a faulty fan motor already. So you either have a faulty fan switch [faulty new parts aren't uncommon] or the coolant in the radiator [where the rad fan switch is] isn't hot enough.

Thanks for the replies.

 

Yes, I replaced the sensor on the radiator but the fan still doesn't come on. I just ran a test with the old switch by wiring it into small circuit with a motor and sticking it in a pan of boiling water on the stove. the motor didn't come on so I can be pretty sure the old switch was faulty. I'll do the same with the new one.

 

Looking at similar topics I can see that it is common for the temperature guage sensor to record higher temperatures than the radiator fan switch so I guess that the issue could lie there although I would have expected the fan to cut in by the time the needle hit the red unless the temp sensor is way off the mark.

 

As the car runs fine and the temperature guage doesn't seem to behave erratically I will test the new switch. If I still can't get to the bottom of it I still favour the manual switch alternative.

 

Alastair