By hand test the temperature of the hoses going from heater valves to heater core. You can also test by disconnecting the wiring connector on heater valves, valves should be totally open at rest state giving full heat.

I would be impressed if the car can actually achieve 85 as I've shown others it's pointless to set the AC to 60; figure out a temperature it can actually achieve (which you determine by turn the temp higher until the fan speed Alex down), same would apply to the high end, though I've did notice TX so if I can get from -10 to 73 it should be possible to get from tx ambient to 85 but you shouldn't need recirculation in that case (other than dirt the initial warming).

FYI my car will automatically switch to recirc when it needs to for example defrost, So I leave the recirc set to automatic. AUC sets to recirc when it's smelly outside

And you have tested that AUC sensor really smells anything? ;)

I have. It will flip to recirculation when the sensor gets to about 2.5v and I've monitored it doing it live when going through a construction zone. Fresh asphalt paving was the test case I used.

I wish there was feedback on the dash to let you know when it was activated but with the feedback from my scanner I did notice the reduction of the petro smell that was shut out.

I'm going to try this tomorrow.


Also, I will completely disassemble the IHKA unit to look at the guts of the circuit board and fan. I suspect there is more dust in there which maaaaaay, be causing an issue. Like I said, after blowing this device out with compressed air, passenger side heat was far far better. I hope this is not a coincidence.

I'm not sure how that left v right temp works when I'm only aware of the temp sensor in the dash. Maybe another in the footwell? If there is and it's shorted it open that could make one side misbehave


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Not trying to be argumentative, but I don't think I've owned a BMW that couldn't reach 85 degrees. :dunno:. Going to have to read vent temps one of these days but they get uncomfortably hot (burn your hand) during coolant bleed process. TX temps where the family wants heat is anything lower than 55f... LoL. Having lived in VA and AR during snowstorms... I laugh at their idea of cold. Having also loved in HI, my flip flops don't come off until temps are in the 30's. :rofl:

Interested to see where the fault lies x5m-ish. Heater valve is left/right and I'm not sure how it affects rear heat.

The cabin temperature sensor you’re referring to: where is this located? I also have a suspicion there are two because of the dual climate zone thing BMW has going on. I’ll pull both these sensors (if there are two), check continuity and clean them. From what I have read thus far these things get fowled over time with dust.

Also several people have mentioned the heater flap. Are we talking a main flap on the driver side that interfaces the interior heater core, or that horn that has the three actuators built into it that close/open when climate control vent buttons are pressed? I know the foot, mid and window vents work and the air output seems regular throughout.

Why couldn’t this happen on the passenger side? Who cares if the co-pilot freezes? It’s all about driver comfort!

The cabin sensor is in the control panel. Has a fan to pull in air. I think there is only one sensor there. I'm not are about left v right I haven't seen left v right sensors other than the heater core temps so maybe it uses those temps and some math.

Confirm your heater cores are both getting hot. What are you using for scanner?


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Heater Control Valve 4.8is Cabin Temperature
 

I think I've read core temps of like 130F normally when cabin is set to 73.

The air coming out should be north of 120 but I've never meausred it.

What I meant about the 85 is like the 60 not realistic to cool a cabin in summer (where for example 66-67 probably quite achievable where the temp will stabilize and the fan speed with slow down). Setting to 85, I will be surprised to see that temp achievable where the cabin got to that temp and the auto fan speed slowed down to keep it that temp. Not staying not possible just saying I would be surprised. Most people would be very uncomfortable if the actual temp was over 80 since that is about the temp people will insist on having AC.

Ambient of 30F ish might be too low for me to do that experiment but I do have to do two one hour drives today I might do it.