Heater fan fault

[lhd]

Is there any way of determining whether it's the resistor or the fan at fault?
The switch seems good,
Many thanks Rob.

[nicq]

On the fastest speed the resistors are not used.
The only other thing to check is the switch this you can check with a meter.
Check you are getting 12 v out to the motor from the switch.

[nevill3]

I stripped my fan heater switch down when I was getting an intermittent fault. When I got it apart (Just a couple of pressure release tabs holding the cover on if I remember correctly) I found that it was "dusty" with carbon like deposits, a quick clean up and re-assembly and mine now works perfectly. Be careful not to lose the small bits that will want to fall out when you take it apart and try and remember which way everything sits before you disassemble it though.

I took this on because I found that when the fan switch failed to work if I pushed the knob in whilst turning it the fan would work briefly until I released the pressure.

[nevill3]

Also did you know the motors are prone to seizing but usually a blown fuse results when that happens.

[pirate-pete]

Now then Rob - hows things.

Just looking through my pics from when my resistor needed changing. You should be able to do these tests without removing dash if you can get to back of switch. You should have a yellow and a brown coming out the heater box. Connect yellow to 12V where it appears at the switch and brown to earth if you can follow it to the crown. That should bypass the resistor and power the fan if it works.

To test the resistor - put a meter set to resistance over the white and the yellow/white (looks like that in the picture but Bentley suggests yellow/black) and take a reading.
Then measure between yellow to yellow/white and take a reading. Think that one should be twice the first reading.
Can also try white to yellow and that should be the total of the two measurements above as the yellow/white is tapped of the windings about a third of the way along.

The yellow from the switch goes straight to the fan motor and is connected there with the other yellow going to the resistor. (right hand side in picture)

I can't remember the resistance values right now but if it has failed would expect one of the readings to show open circuit and the other to show something in the low ohms range depending on which end of the resistor has the break.

Just thinking too if the brown has a bad earth then fan won't work.

[lhd]

Thanks to alll for taking the time to reply,should help no end,,,,
Thanks for the pics Pete, hope your well.
I did the hire vans fan easy enough, this is my brothers, just didn't want to waste money on the resistors for nothing,although I didn't realise they were only £16...lol
Rob..

[CovKid]

Cheaper still to fit a variable fan controller. No need for resistors and you can have any speed then.

http://www.ebay.co.uk/itm/12V-24V-48V-6 ... 5b0f847bb1" onclick="window.open(this.href);return false; or similar.