Another Heater question but is basic!

No. But a functioning heater valve will click on when it opens and closes.

Yes. The heater relay connects the ground to the valve when you press any of the three buttons. It's then controlled by the ecu via a 12V input.

Yes. Mine worked after I cleaned it out with WD40, re-oiled the bearings and replaced the condenser and resistor.
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How do you actually get that little motor out, I can't even see the harness connector i that tight underdash area?

 

The heater valve can cycle on and off during adjustment, but not always. It is controlled by a small "computer" box getting signals from 3 sensors. I think the cabin temp sensor is the one with the little fan on the dash, and there are two sensors in the heater box and its ac evaporator coil.

The heater valve is either open or closed (it's default is in the closed position, such that if it fails you don't get the heat). In order to modulate the temperature to the input on the control knob, the computer senses the request for more or less heat, interacts with the sensors, and then the valve can cycle on and off as a way of reducing heat flow, as the valve has no other way to do an intermediate type of flow rate of coolant through it. So I would expect you would have the valve cycling when reducing the temp from full heat and where the ambient temperature is quite warm already, but I have not really paid attention to when I have heard this cycling going on.

Fyi, there is (or at least there used to be) a rebuild kit for these valves. It is made by MTC and has BMW part number 64118390132. The heater vale is referred to as a "mono valve". The same heater valve as the Ferrari used was also used in Bently's of the period.

I beleive Superformance in the UK sells the rebuild kit.

https://ww3.aitsafe.com/cf/add.cfm?userid=5369319&product=Heater Tap Overhaul Kit 61079000/RK&price=189.90&units=1

https://www.pelicanparts.com/More_Info/3065.htm?pn=3065-INT

Hard to know is the Superformance kit is identical to that from Pelican, but unless they have some NOS from when the French supplier to BMW for this valve made the part, it is probably the same Chinese made MTC item.

Summit Racing used to sell just the rubber bits and you reused the old tube/spring piece. Those lesser kits are probably still out there.

As long as the failed seals inside did not cause coolant to leak into the electrical area that could damage the solenoid, the rebuild is the way to go. Typically it is just the little plunger seal that degrades, not the gasket seal of the tube to the solenoid are.

 

Correction, the heater valve is always actuated with 12 volts when the car is started, and the plunger snaps up, and no heat is let through unless called for. If the solenoid fails or the 12v is not there, ie. if the valve fails the spring in the plunger snaps it into the heat allowed position.

If the valve is leaking inside, you might be getting heat when you don't want any, and can cause people to think the ac may not be working.

I think I have all this correct! There are some counter intuitive things about how this system functions!

 

The reason for the heater valve being open when not powered is so you can bleed the cooling system without the car being electrically powered up.

 

You need to unbolt the lower dash corner; bolt hidden behind the wheel well carpet.
The motor/fan in its housing can be pulled off the U-shaped tube without the need of removing the air intake. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login