Radiator fan not working - strange electrical problem

[Simon.H]

I have a manual fan switch setup on my car which I've used for some time. On Monday evening it wouldn't always work so I have replaced the switch today with a brand new one with an LED in the end to visually indicate a current.

 

Anyway, now the fan doesn't work at all, either with the new switch or the old one. However, the LED lights up nice and bright, which says to me the circuit is complete and the fan *should* be working.

 

My circuit is: battery -> fan -> switch (20A) -> fuse (15A) -> battery

 

If I disconnect the fan or the fuse, the LED does not light and the circuit isn't complete. I've tried moving the fan blades in case they were stuck, but nothing seems to work. Is the fan dead?? Just seems strange the circuit would complete

 

Simon

niknak.org

[shn7]

Try putting 12v direct across the fan. That should tell you if it's dead or not. Mind your fingers though.

 

Steve.

Not forgetting Percy the Polar Bear who recommends

Puddle Pet Care

[Bob_Rich]

Hi

 

A lead to the battery direct as above is a good idea but DONT touch the bare wire with you fingers you could get a (electric) belt from the motor back emf when you pull the lead off!! could be the brushes are a bit worn and sticking. try a sharp tap with a mallet on the motor body to see if it comes to life. To test the circuit to the fan remove the wire to the fan and wire a bulb to the lead with the other side of the bulb to a good chassis earth . operating the fan switch should make the bulb light.

 

hope you sort it

best of luck

 

Bob

[elie boone]

I would do - battery - fuse - switch - fan - earth or if you plug into an existing system ( thermo contact )the lead from the switch has to go to the lead that goes to the fan.

[Simon.H]

Thanks for the tips everyone. First thing tonight I tried putting 12v straight across the fan, and it worked fine. Traced it to the switch. It's got three connections labelled power, acc and ground. I was using power and ground, which is good for the LED but not the fan, it would seem. Power and acc on the other hand, works for the fan but not the LED.

 

I don't really get electrics to be honest, so I'm just happy to have it working again and intend to leave it at that for now! 😬

 

Simon

niknak.org

[jradley]

You need to connect the pin marked "ground" on the switch to the vehicle earth (battery -ve). It is correct that the +ve from the battery goes to the pin marked power and the feed to the fan is the ACC pin. Then, when the switch is on the light will illuminate.

 

Cheers,

 

John