318 - E46 2000 model NO HEATING. HELP!!!!!!

I have a problem with the heating system in my 318. I push the button to display 32 degrees for example and get no hot air coming from the vents. That's any of the vents. The fan/blowers work at low speed and high speeds. And the blower speeds up when on auto controls. I have checked all fuses relating to anything to do with heat controls and they are all fine. I have changed the heater valve. It was second hand but what's the chances of a second valve not working? And still no heat. I left the heater valve disconnected from the electric which in turn left the heater valve open therefore letting hot water through the system. This surely proves the system works. But as soon as I put the electrical connector back on it closes the valve back up and stops working. I have also cleaned the little filter on the control panel this also had no effect. I'm really stuck now? I got told about the final stage resistor but this only controls the actual fan speed so I ruled this out to. Any help would be really grateful. Thanks

Did you bleed the air out of the heater loop?

Hi. I was thinking the heater Matrix maybe blocked have you tried flushing it out? Jim

Originally Posted by jcjdavis1

Hi. I was thinking the heater Matrix maybe blocked have you tried flushing it out? Jim

Hi I did think matrix but surely if it was the matrix I would not get hot air at all. But when I disconnect the electrical connector on the heater valve which by default opens the valve I get hot air. ????

From the middle of the dashboard vents, did you turn the dial to "heat" (red) ?

Originally Posted by joegr

Did you bleed the air out of the heater loop?

No didn't bleed the air out of the loop. But as mentioned above a can get hot air when I disconnect the electrical connector from the heater valve. This allows flow round the system

Originally Posted by GroupBquattro

From the middle of the dashboard vents, did you turn the dial to "heat" (red) ?

Yes tried his. Usually always on red

OK then. Old school diagnostic now, can you follow the hoses that go to the heater core? I did it once with an old car of mine, I kept following all the hoses that led to the heater, touching a hot one, hot, hot, until I reached one that was cold and wasn's supposed to. That's where the problem was.

Originally Posted by GroupBquattro

OK then. Old school diagnostic now, can you follow the hoses that go to the heater core? I did it once with an old car of mine, I kept following all the hoses that led to the heater, touching a hot one, hot, hot, until I reached one that was cold and wasn's supposed to. That's where the problem was.

Tried this, both pipes at the heater valve are cold until I disconnect the electrical connector then pipes are hot as soon as it behins to flow through valve.

The issue seems to be getting the valve to open. I don't know the electronics behind how it all works so not sure what makes it open and close.