Another Heater question but is basic!

Hi Team just a quick one for the brains trust.

I am in the process of replacing my heater valve on my QV and whilst I am waiting for the part to arrive, I thought I would check a few things before I put it all back together and have the aircon re-gassed as it is currently empty thus not allowing the compressor to engage. I have scrolled through pages of info that had been extremely helpful.

I have tested the resistance of 3 sensors and all are in spec.

I have replaced the heather relay (SPIPA 0440) and repined 87a as per instructions on the forum.

My question is, is the heater relay supposed to click on and off when adjust the heat setting knob?

It currently clicks when press any of the 3 AC buttons and when you also hit the stop button which I believe is correct.

Second question is with the suction fan as mine is not spinning. It has power to it so, I am wondering I the little motor is ceased. Its clean and looks in great condition. If I put 12 volts and earth to either side of this motor to test it, it should work right?

See pic below of the suction its next to your knee.

 

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

 

My solution to the heater valve leaking.
Alden
https://www.ferrarichat.com/forum/threads/installing-a-heater-cut-off-valve-1988-3-2-cabriolet.696939/

 

This great info, thanks everyone for the responses.
Im pretty sure once I receive the rebuild kit for the heater valve it should all work, however the suction motor is what I am suspect on.
Thanks for the detailed pics Afterburner I couldn't find much info on them.
I will try (with my basic electric skills) to put 12v at either side and see if it spins, if not I will lube the bearings and get a new 5ohm resistor.
I really appreciate everyone's responses as I was stumped!
Enjoy the weekend, I will be playing in the garage!

 

Ok so finally got around to inspecting the 12v suction motor for the climate control system.
Cleaned it all up put power and an earth to it and it works!
My only question is mine has a resistor in one of the wires and yours moysiuan has what looks like a capacitor.
Moyiuan is yours original? Or has mine been modified? And should I delete the resistor and put a capacitor in there.
I not sure who many people have gone to this length but any guidance would be appreciated.

Ned

 

Ned great this worked out. I had to replace my motor at one point as it kept mechanically seizing when it got warm. I bought a second hand unit from a Mercedes (white housing) and it did have a different setup with only a capacitor from the original Ferrari unit (my first photo with a resistor and a capacitor). Both worked without interference to the rest of the electrics in the car.

 

Perfect, thanks Afterburner
There is no way I would have any idea about this without your help, greatly appreciated my friend!

 

Pleasure