vjd3

Mine did that exact thing a few years back, Mike ... Jerry put it right, it had something to do with the fuse block at the back of the car, if memory serves ... relay, blower motor, something.

nile13

Vic, that's what I originally thought as well from my previous car and Randall's help back about 6 years ago. However, after some searching it turned out to have been a different issue.

Back then I didn't have much airflow other than on highest setting. It turned out to be a defective rear blower relay. So maybe that will help someone who's having that particular problem.

I'll take the car somewhere if I have to. It's just that these kinds of problems... I dunno, just feels like I should be diagnosing and learning how to fix them myself. Than again, I've been delusional many times before

nile13

Dave, yep, Hammer is a good thought. Jerry or someone closer by in Boston might come handy.

irideducs

Maybe "hearing a flapper"is not the right terminology. When the heat is at almost max and blowing luke warm air with the blower motor set to 4, I then move the thermo to the red dot / MAX and the flow of air transitions from blowing noisy /hard, to a slightly slower, softer and very hot air stream. I have both sliders set to full left when testing, so everything is coming out of the dash. Seems like everything is functioning properly, except the CCU is not communicating heat for anything but a full MAX temperature setting.

Again, mine works as it should when I first start out (includng the air flow transition I described, but at lower temp settings), but then reverts to this behavior after I have been driving for a little while. Does yours do that?

nile13

If I remember Randall's explanations way back when, the Red Dot and Blue Dot positions essentially bypass anything that CCU thinks and say: "give me full hot" or "give me full cold". A very German engineering thing - build in failure mods and then come up with complicated ways of dealing with them

Essentially, yours behaves pretty much the same as mine. I dread a dead/dying CCU. Think it's time to pull it out and try to re-solder the contacts and see what happens. Used CCUs go for $400+ now and repairs run $300+ by shops. Not pretty.

irideducs

Let me know what you find out.

Akerlie

Paging Toreb

meanwhile you can check out his webpage : http://privat.bluezone.no/toreb2000/ccurepair.html

nile13

Akerlie, this is the greatest thing since sliced bread. Exactly what I needed. Thanks, man!

I knew that SE people help each other more than others

nile13

A bit of an update. Blew some compressed air into the little grate that houses air temp sensor inside CCU. Ran out of compressed air in a can long before I felt it cleaned much there. Today the heat was sometimes on, sometimes not while setting at 27C mark or so. Which means that I'll be talking CCU out and looking at its fan as well as cold solder joints and all that wonderful stuff. If I could get another CCU to try out that would make it simple.

ToreB

Hi there!
I would not use compressed air in the CCU temp sensor, it could over-rev and damage the CCU fan at the back. I would suspect the two mixing valves to be the culprit if you are having problems getting hot air. Check the operation by opening the kick carpet panels and look for motion as you turn the temp **** from min to max and back. Both valves should close and open accordingly.
Damaged valve servos is a common problem. If both of them are stationary you may also have a problem inside the CCU with a driver IC. But that's another story, check the servos first.
Cheers,
Tore
www.ccu.tore.bergvill.com

nile13

Tore, thanks!!

I'll check the servos at the footwells. What is strange is that both servos would go bad at the same time. On top of that, the problem seems somewhat intermittent as they seem to work for a time yesterday.

ToreB

I agree, it's rather strange. However, intermittent behaviour in defective servos are common. A good bash can make them work for some time. You may have to disconnect the valve from the hoses to be able to spot any motion. I have changed both my mixing servos though, but both are driven by the same output in the CCU, so your problem may be inside it.
Cheers,
Tore

MrBonus

My car has developed the same problem with the a/c, Mike. I'll keep an eye on this thread.

irideducs

Old thread, I know, but did you ever find the solution to this problem? I just had mine in for an oil change and checkup. No codes for flapper or any heat related issues. One code for an A/C sensor (max A/C was blowing at 60 degrees at the vent, which is a little warm), but the tech swore it could not be connected to my problem with the heat only working at the max setting.

01coccobet

AC is the actual problem for many of us...

hope to hear some good news...