Had my cars water temp upto 115 today and still no fan.

One wire to fan thermo switch.

If I earth this wire - fan comes on.

How do I test the thermo switch without taking it out of the rad?

Thanks,

Pat...

sounds like you just have!!

I would suggest that you take an ohms reading at cold and at hot, if they remain the same, the sender is goosed but to be honest it sounds like it is goosed anyway

[Edited on 28/7/07 by macdave69]

Pat
sorry if this is stateing the obvious but does the switch have two wires of which one is from the fan and the other is to earth. if so then if the earth connection and wire is ok then the sender is faulty. i just reads as though you only have one wire connected to the thermal sender on the rad.

rich

On one we had the sender had 3 connections but one was blank and the connector had two wires and one blank, but one of the wires was to the blank connection on the sender. It took two overheats to spot the problem. We used the thermostatic switch to earth the fan relay.

firstly, since you have a manual and i don't, are you absolutely certain it is the fan switch? i know the temp sender's in the thermostat housing, but is it absolutely definitely a fan switch?

secondly, have you tried a direct earth for the radiator? it's mounted on rubbery bits so might not be earthing properly.

just musing.....and if it's neither of the above, sounds like the switch is fubar or maybe the relay, though i can't remember if you've used one or not.

tom

No relay.

Fan switch is in the rad and only has one connection.

As per the manual, 12v to fan, 12v out of fan to switch. Switch supposed to earth when it gets hot.

Hi Tom - I though of that after the first 20 minute idle, so directly earthed the rad, but no difference.

No change in hot/cold ohms either.

Sounds like a new switch is in order.

Tom - might need you next weekend to trim it all up!

Prob off to Mac1 on friday as well if your game.

Pat...