Heater Stuck On Hot

[Chimneys999]

Hi

I have a 2001 1.25 Fiesta. About 2 weeks ago the heater only produced hot air. I suspected the heater valve and replaced it. Same problem i.e. the valve doesn't close off the hot water flow to the heater matrix. Testing the electrical input I get about 6/7 volts with the heater dial on hot, reducing the heat produces a pulsed voltage which reduces down to zero with the heater off. The power doesn't seem to trigger the valve. Shouldn't the power be 12 volts? Why is the water flow stuck on and not off with the power disconnected? Any help appreciated.

Chimneys999

[Eldon]

Hi

We have a similar problem. We tested the voltage and we have 12 volts on hot and 12 volts on cold (but still blowing out hot)

We tested a neighbours fiesta and his is 12 volts hot and cold. Were the pollen filter is the air temperature when the blowers are on is really cold. We removed the pollen filter which was block with dust and dead flies and this made a slight difference. I think we will have to pull the hot and cold switches apart and have a look to see if it is working properly.

Regards

Eldon

[Alfiesred]

this is a very commom fault,its usually the heater control valve.

[Eldon]

Yes it was the heater control valve. The car went in to have the catalytic converter replaced and when my partner went to do the weekly check she found there was hardly any water in the rad.

The garage had snapped the heater control valve (how you can snap that i don't know) the garage put a ford ka one on from one they were selling and it turned out to not work it was always stuck on the open position.