I have a problem with the heating in the car...not good in Ireland in November.
The vacuum heater valve at the firewall is operating, I can see it open and close when I turn the temp control from cold to hot, and the pipes running in and out of the heater matrix are hot.
I get air from all the vents, face side and foot, but the position the temp control knob has no effect, the air is always at the outside temp, ie cold. My cooling/ac isn't working (and has never worked) but I never really need it (summer in Ireland is not too hot!), but I do need the heating!
When I turn the control to defrost, the fan speed increases and air comes out of the defrost vents under the windscreen but continues to come out of the face level vent.
The slider for the face level vent has no effect on the temp of the air coming out of it, but i'm not sure whether it ever has?
I'm guessing I have a problem with one or both servo's that move the upper and lower blend flaps?
Any pointers on where to start with this?

 

I wish I could help but I have the exact opposite problem. Continuous hot air from the vents regardless of the position of the controls. I'm assuming I also have a problem with the flaps and or servos. The issue is that it's a dash out problem to remedy. No fun there.

 

If I had this problem my first thought would be to warm the vehicle up with the heater on, then feel all the cooling system pipes to see which ones are hot and which are cold (probably starting with the ones that go through the heater core). If you have a blockage or something stopping the hot water from flowing through the system, this might give you an idea of where to start looking.

I'm sure someone who knows your vehicle better will chime in, but hopefully that idea might give you a head start.

 

Quote:

I'm guessing I have a problem with one or both servo's that move the upper and lower blend flaps?

I'd begin by cleaning all the tiny-wire connections for the climate control. There are a half-dozen or so, some easy to see and touch, a couple not. They have very thin wires and white connectors/plugs. A couple are located quite high, just below the dash pad. Often they're packed with green corrosion and the servo motors won't work as a result.

I've fixed a couple misbehaving, non-responsive systems by cleaning these connections/plugs.

Cheers
DD

 

So I finally got round to investigating this yesterday. Engine running, turned the temp knob for max heat, medium speed on the fan, cold air. Took off the right hand side transmission tunnel cover with the footwell vent in to have a look. The intention was to clean the connector to the climate control unit ECU as suggested by Doug, and maybe see if I could remove the flap motors and see if they move when disengaged form the blend flaps. It did seem suspicious that BOTH blend flaps weren't moving so a mechanical fix due to something sticking seemed v unlikely.
So this is what you see with the cover removed;



Ok, Holy Cow, there's no access to anything... I thought sh&t, I'm probably going to have to take the dashboard out as all the threads have been advising.
I was poking around and my fat fingers brushed a two wire connector block, just nestling on top of the footwell vent duct and below the ECU, the one in the close up photo below .... and it just fell apart.



I thought I couldn't be that lucky, pushed the connector together, got a nice click and hey presto the air coming out the vents started to warm up, within a few minutes lovely hot air.

Now I haven't looked at the wiring diagram to see what that connector is but hey... what a result. Made my day!!
Now the last time I was under there must be at least 5 years ago or more. I removed both passenger and drivers side blower motors (what a bitch of a job) to replace the Darlington transistors and one of the vacuum actuators. Must have pulled or disturbed that connector, and it finally fell apart a month ago!!

 

Checked the Delanair 3 wiring diagram, purple/red and white/black wires appear to be the lower flap servo. So it seems my lower flap was inactive. I thought both had stopped. Maybe the top one needs some feedback from the lower servo potentiometer before it can do its stuff..

 

For the love of god can you please post this wiring diagram?!

I have a very similar issue the car is hot as can be expected in 8c temperatures after a good run or idling in city traffic yet my hands are numb from the barely not-even-luke-warm temps out of the vents, the servo wirrrrs back and forth going from cold to hot but I think its not going far enough. Lower air vents are dependent on the alignment of the planets it would seem. Some days "warm" and most of the time ice cold despite somewhat warm-ish air out the top.

AC works brilliantly though I just spent thousands redoing it all thats nice in summer but not now.

Is there not a way to manually force the system to STAY in max heat I don't need 60% cold air blending in for god sake.

 

Here you go! See page 7 of the attached