We have a 2005 Ka collection and it is constantly putting hot air into the cabin as the engine warms- with temperature set to cold.
Both hoses to and from heater valve get very hot.
I got a heater valve off ebay - didn't make a difference.
I got a replacement facia - no change.
I then got a heater valve from ford- still no difference
( I thought it was working though as it felt like it gave cold air for a minute or two. Then back to red hot!)
I found another control unit so tried that- no change.
Fuses are ok.
Today I disconnected the multiplug and connected it to both valves in turn, set the temp in cabin to mid position so should be pulsing?? ( engine running)
No movement whatsoever .
I tried the test with all 3 facia's and the swapped the valves.
No movement.
I have heard there is a resister near where the passenger right foot would be.
Is this just for the blowers or does it impact the heating in some way??


I have run out of ideas
Can anyone suggest anything to try next.
thanks

 

The resistor is just for the fan speed, it doesn't control temperature. I would say it is probably a wiring problem, I guess these work on a stepper motor type setup, so I would be checking for change in voltage output at the plug when you turn the dial.

 

thanks ,I forgot to say that I have had a meter on the plug contacts
Across the pins of plug measured 0v
live to battery measured 13v ish
the pulsing one measured between 0-0.3v depending where the temp dial was. (to battery)