I have a 90 C2 cab with A/C.
The heater control **** scaled 1 to 4 for
the blower speed works fine until I try
& turn it off ( i.e. to O )
Then it keeps going & also varies it's
blow rate on it's own.

Any suggestions as to the fault?

Thanks in advance.

Nigel (Holland)

 

Nigel

This is not a fault. you have 2 ***** - one for temparture, and the other for fan speed. Regardless of temp or fan setting, there will constantly be air circulated into the cabin. This is just the way it is.

That's the technical explanation, I guess Adrian or someone will give you the simplistic/layman terms explanation !

 

Dear Nigel,
I think you need to explain a little more. The fan when selected off should turn off and stay off. However if you have heat selected the rear blower fan will keep operating. This will keep warm air blowing in as long as a heat selection is made (above around 21-24). If you are saying that your LH blower fan (speed controlled one) is still running and not switching off and is changing speeds, after you have turned it off using the speed control ****, this is a fault.
What can cause this fault.
Wrong aircon/heating control unit installed
Rear Blower Fan fuse blown (found on rear engine bay carrier plate) "Most Common".
Control Unit failure.
Blower Final Stage Failure.
I would check the blower fan fuse in the engine bay first.
However before looking for a fault please ensure that the LH Blower fan is actually turning off and the rear blower fan keeps operating.
Ciao,
Adrian
911C4