Heat not hot

[absentmathis]

I noticed today that my heat isn’t very hot. It’s warm, and all the settings including idrive are set to hot, but it’s not getting up to normal temp. As a secondary and likely related problem, the auto climate control doesn’t seem to be working. I crank temp up to 84 and put it on intensive but fan speed doesn’t change (at all that I can tell). I can think of a few potential issues including water valve and tstat, but I’m hoping someone might have some insight? FWIW, BMW replaced my passenger airbag few weeks ago and this may have been going on since then. Everything else seems functional but I’m wondering if when they pulled the dash something got left unplugged or damaged. They botched putting the dash pieces back together so it’s going back in a couple weeks, but in the event this is unrelated I’d like to get ahead of it.

[andrewwynn]

Ambient temp? Use hidden menu for monitoring coolant temp.. I had similar symptoms and it was the tstat


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[absentmathis]

It’s been in the 30s. Good call on checking coolant temp. I’ll do that with hidden menu or Carly. Should be what, about 220 range? Guess it would make sense that if heat isn’t getting to temp that the auto climate would be holding back like it does when the engine is still cold.

[absentmathis]

Coolant temp is low to mid 90s(c), which is in hindsight a bit higher than I would have expected but to me would indicate that it’s not a thermostat problem.

[ard]

"a couple of weeks"?!?

I'd have bought it back the next day....

[absentmathis]

Originally Posted by ard

"a couple of weeks"?!?

I'd have bought it back the next day....

It hadn’t been very cold and either I didn’t notice immediately or it wasn’t caused by that repair. Then holidays. And now I’m just waiting on first loaner appointment. But I hear ya. They said I could bring it right when I first called them. I checked codes yesterday and under heat/AC I have a KCAN error e729. Not yet sure what it means or if it is returning.

[seattle]

Be sure they (SA) records this as you stating this heater issue is related to the botched dash install. Have them specifically check all connections.
Of course, they will try to persuade it is a separate issue and recommend chase it with expensive part replacements.

[andrewwynn]

I just re-read your post and the most important comment I missed. "fan speed didn't change" does it blow at all and can you manually change the speed?

If you can't get the fan to change speed (on auto it will show the speed it should be = mad when demand is much higher than current cabin temp) then it's pointing at the porcupine. It could be a wire that was knocked off but porcupine controls the fan so if the fan speed is wrong then either porcupine is not doing its job or it's not being told what to do (or the blower motor likewise getting no power or broken).


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[absentmathis]

I can manually change the fan speed and it blows at whatever speed I set it at, but best I can tell “Auto” isn’t adjusting the fan speed at all. But I wonder if that’s a side effect of the air not being that warm. In other words, I agree that it should be blowing like mad when set to max heat, but the system is smart enough not to blast you with cold air. When you start the car cold and set auto, it typically slowly adjusts fan speed up as the air warms up. Eventually it’s blasting you if it’s still cold inside the car. But when the air is lukewarm, like it currently is, auto should be blowing at about a “2” fan speed (which it is). Does that make sense?

Would you elaborate on this “porcupine” a little bit? Seems like that may be my culprit, and I wonder if I can trace this KCAN code to it.

Also, FWIW, when I crank the temp setting all the way up to 84, the air does get just a bit warmer, but fan speed still doesn’t change.

[andrewwynn]

But if you MANUALLY change the speed of the fan will you get hot air and get the cabin to a good temp?

The thermometer for the cabin temp is right behind a tiny little grill near where you disable the DSC. Clean that out with a tiny brush (I used the little tooth floss brush). Wife's car would not cool to set temp when that got plugged. Cleaned it out and it worked. If the air is blocked and heat from inside dash is warming it up you could be experiencing the same problem.

The porcupine is the nickname for the FSR or FSU (final stage resistor|unit). You will know why the nickname when you see one. Maybe more like a hedgehog.

Unclear from your reply: when you change the temp higher you should see the fan speed indicator rise. Does that happen or not?


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