I get a lotta heat or I get ice cold A/C .... nothing in between !

[CoconutPete]

So this is kind of an odd problem.


If I turn on the A/C and crank the knob all the way to cold - I get ..... ice cold A/C. Nice!


If I turn the knob any distance at all away from the coldest setting then I get heat. A lot of it!


There is no in between.


The a/c clearly works. The heater clearly works. Why the hell do I live in a world of extremes?


The back of the switch panel looks fine. These symptoms do not seem consistent with the final stage resistor problem.


Any other ideas?

[magnetchief]

The temp control only controls the air blend flap.
So if you have only hot or cold I would guess there is an issue with the flap.

A bitch to get to. But removing the glove box will give you access.

Maybe that would give you some idea as to what’s going on.



Sent from my iPhone using Tapatalk

[Vintage42]

Read down to #11 in this thread to see if the problem sounds like a sticking blend door, and see the fix:
https://www.bimmerfest.com/forums/sh...ght=stick+knob

However the problem could instead be in the controls as here:
https://www.bimmerfest.com/forums/sh...0&postcount=45
It says:
"The switch moves the cable via a snail cam track, in which the white lever lug is supposed to slide. My lug had jumped out ? unlikely, or was never correctly assembled. The result is that the temperature flap cannot return from HOT, (there is no spring return mechanism), and , as soon as you move the knob from cold you activate the hot water valve via the microswitch and you cook. My air flap had NOT stuck to any seal..."

[CoconutPete]

I see some similarities, but most of those other threads start with "my heater control knob has broken". Mine still "works" in the sense that it can alternate between hot and cold, it just only provides extremes. I suppose it could be the same thing though.


I happen to have the center console out of the car, so it shouldn't be too much more work to remove the glove box. I'll give it a shot!

EDIT: Nevermind, I just re-read the last part of what Vintage 42 wrote. I think this definitely seems like a contender!!

[Tim95M3]

Both of my zeds are similar. The only range of "warm" is almost all the way over to heat, but not quite at the "click". I've just assumed it's normal and got used to it. I mean, I'm in TX so I need A/C one day and heat the next.

[daven]

Normal behavior for me. Turn in on full and moderate back to desired level. Not there is that much fine tuning available.

[jrkoupe]

Normal behavior for me. Turn in on full and moderate back to desired level. Not there is that much fine tuning available.

not much at all......

[Tigershark48]

Interesting. I took my very second ride yesterday. Getting slightly cold I adjusted the temp upward. Not much effect until it was max heat at which point I was cooking. Turning it down a bit started getting cold again. Good to know this is normal. I’m not worried, since it’s strictly a perfect weather driver for us. Yesterday, I had to do its first emmisions test due to recent purchase. Back to winter storage today. Next year, collector plates with one time registration fee and no more emmisions tests.

[MartyBtoo]

My temperature control works about the same as yours does. On my car the more effective temperature control is the fan knob; raising or lowering the fan speed makes a difference in the heat it puts out.

Marty

[Tigershark48]

Nice workaround.

[CoconutPete]

Well, the forum strikes again!
I yanked the heater control module out and took it apart. The little "nub" that turns the plastic thingamajiggy that pulls/pushes the cable was indeed broken off! With the electrical contact at the end of the hot/cold knob it's easy to see how it switches electronically between hot and cold but there's no cable to provide anything in between.

I bought a small pack of M3 screws, stuck it in a drill bit and used a dremel to slim it down a bit. Then I filed the plastic piece flat and drilled a hole slightly smaller and threaded it in. Assembled everything and slathered it in silicone grease. It seems to work beautifully now. We'll see more when I get it assembled.

[Tallyho322]

I broke my “white” control arm this summer. Took it apart over T’giving and use a ball stud (from a R/C plane) to replace the broken stud. Similar to your application, but the ball stud can screw into a small hole drilled in the arm. No modification required.

Working on the Air bag module now. Just got it out and sent it to Abel for a reset.

Still cant get the center console out though. 2000 Z3M Roadster...anyone have any tips?

Greg

[CoconutPete]

Wow, I seem to be the only one who did not use the hobby ball stud approach. Oh well... my modified M3 screw works.

It was Friday night, the kids were sleeping and I had a glass of bourbon and music on out in the garage when I took the center console off, so I did not keep copious notes. This is a pretty good guide though.

https://www.pelicanparts.com/BMW/tec...eplacement.htm