I've been searching quite a bit on this topic and I seem to be just spinning wheels. I have no heat in my car (also don't have AC but one thing at a time). This is a Klimatronic unit.

Things I've tested/replaced so far:

• new thermostat and senders (not really relevant other than to say engine is idling at 80* C)
• 5 of the 6 valves on my tree of six weren't working, so that was completely replaced. Tested and all valves now fire.
• vacuum at the tree of six is 19 mm Hg so good vacuum
• tested all the vacuum (mightyvac) actuators, 3 appear to be working
• replaced the fresh/recirc actuators (both of them; 5 & 6 in photo below)
• need to find a vacuum leak (possibly replace) on the defrost vent which I'll tackle at a later time, i believe number 4 in photo below.
• Additional testing on the center vent which I believe is number 3 below.
• replaced the monovalve
• I do have voltage at the valve when the heater is on
• I can feel heat on the inlet and outlet side of the heater core in the engine bay

Now the issue, just no heat. Drove into town yesterday and it was about 50 outside. Engine was up to temp so I put the heater to 26* i was getting cold air (outside temp, not AC cold) out of the vents.



My question: do I suspect the heater core and start looking at replacing that or is there a, what I call, blend door that may be suck in the AC direction? How do I check the actuation of this blend door? Does the blend door typically fail in the AC position?



I've been referencing these two photos. I've been assuming this relationship (please correct me if I'm wrong):
38 valve is number 4 (only valve with 2 inlets)
39 valve is number 2
40 valve is number 3
therefore 41 is number 1








The photo below is from a class 2 W126 so it has the tree of seven which doesn't have the orifice between 40 and 38 like the class 1. Also uses a different foot valve but that's not relevant. But it would seem logical that 41 is the blend door (diverter flap?) to which I reference. Am I baseless in my assumption? If so, I would think 41 in the above photo would also be the blend door. Which would lead me to believe valve 1 in the photo is where I need to look. I'm confused by the 1985 service manual which calls 41 a "scoop air flap". Does "scoop air flap" mean diverter valve (blend door)? If so, I think I need to focus some attention there.








Do I need to focus any attention on temp sensors? Right now I'm using the extremes of the temp setting (high heat until click) so I would think the temp sensors are being 'ignored'.