Technical how to test radiator fan switch?

[leebex]

Hi, my radiator fan doesnt come on when the water temp gets too hot, ive checked the under bonnet fuse, and cleaned the terminals, changed the fan, as it was siezed.

Im thinking that possibly the rad fan switch isnt working, as if its duff, it wont tell the fan to come on, whats the test procedure for a switch?

and can it be done with it fitted or removed? I have also fitted another, and fan still doesnt work, although it was a second hand item i had laying around so cant be sure if it works anyway.

If still no luck, whats the best way to switch the fan as and when I need?

Lee

 

[Rustbucket]

Hi, my radiator fan doesnt come on when the Lee

Test the fan by putting 12v direct to the fan motor. Mind your fingers! You can also check that power is getting to the switch by using a 12v bulb in the circuit.

 

[D4nny8oy]

Disconnect the switch and bridge the terminals (note: use thick wire that'll handle the load without melting in your hands!)

 

[leebex]

fan tested with 12v direct from battery and its working fine. I bridged the terminals of the fan switch and still nothing. Rechecked the 30A fuse under the bonnet, and the fuse in the main panel under the dash below the steering wheel.

Are the relays behind the panel in the glove box anything to do with the rad fan?

Im really thinking Im going to have to bypass it all and fit a small switch in the dash, possibly use one of the blanks and fit another fog light or something.

Does anyone have a scan of the rad fan wiring so i can trace through to try and find a fault?

if I do have to add my own switch, the wiring looks fairly large, 1- 1.5mm possibly 32`s or 30 strand wire?

Thanks, Lee

 

[D4nny8oy]

Simple. If bridging the fan switch wiring doesn't make the fan work (ignition has to be on), then the fault is probably in that short loom. It's less than a foot long, so unwrapping the tape won't take long.

A friend's Punto had corrosion in his- chopped it out and repaired it, and all was ok.

 

[leebex]

Ive got a spare loom of that short section on the rad fan bracket, so will try that, and unwrap mine just to see what is like.

I did check the plug and socket connections at the top of the rad where that short loom section meets incase the terminals were corroded, but didnt think to check the wiring further, other than to make sure fan switch and rad fan plugs wernt corroded.

Thanks