HEATER FAN

citronut · Post by **citronut** » 17 Oct 2010, 15:45

on the way home yesterday eve i tried to turn my fan off, it wouold not respond to anythig, so when i parked up i pulled the wires out from the 4 pin plug, they were very hot,

i suspect there is a melted wire although i did not smell any hot plastic,

regards malcolm

handyman · Post by **handyman** » 17 Oct 2010, 18:10

Hi Malcolm, sounds like the contacts in the ignition switch. Is it in your Mk1 estate?

Later models were protected by a relay so the contacts could not burn.

H

citronut · Post by **citronut** » 18 Oct 2010, 12:50

can the contacts in the ignition switch cause the fan to not respond to the fan control switch, as it was running full speed even with the fan switch at the off position,

regards malcolm

Clogzz · Post by **Clogzz** » 18 Oct 2010, 14:16

Full speed all the time is usually caused by shorted transistors on the motor board.
If you fancy a dabble in soldering, Chief Jim has posted a repair guide:

http://www.frenchcarforum.co.uk/forum/v ... hp?t=22348

Otherwise the board would need replacing with a known good one.

Regards, Terry.

citronut · Post by **citronut** » 18 Oct 2010, 18:37

again is that so if the fan is on full whilst it switched off,

yes i have done the replacement transistors on my daughters pug 406,

regards malcolm

Clogzz · Post by **Clogzz** » 19 Oct 2010, 12:08

Yes, shorted transistors bypass all the speed regulating electronics to cause the blower to run flat-out as soon as the key is set to ignition, and before the engine is running.
Shorted transistors short the feed straight to the motor.

Normally, the engine has to run for a second or two before the electronics can start the blower.
With shorted transistors, the blower motor won’t even know where the speed slider is.

Regards,
Terry.