Hello, hope someone has new insight into this problem. I am stumped.

Have hunted the forums extensively and not found this exact problem. Similar, but not the same when you dig into it. Most are complaining about too-much heat. That would be preferable at the moment.

2006 E61

Great heat on passenger side, no heat on driver side. Defrost vent is hot from center all the way right. Only a small section on the very center-left is cold and driver window defroster is cold air.

What I know so far:

Using INPA and ISTA+ I can manipulate the flap motors and air flow seems to change accordingly. Coolant seems to be flowing to both heat cores because both hoses are hot and INPA shows the same temperature on each core. Have changed the heater valve just to rule that out. Water pump and thermostat had to be changed because of a leak. Of course bled the system numerous times. The driver heat problem predates the new water pump change.

Watching INPA or ISTA, the flapper motors change position based on control inputs and have matched them on both sides. Still no driver heat. Driver is calling for heat, just like passenger side. Manually setting the flapper position in INPA does not change the situation. I have initialized the flappers a few times, no change. There are no error codes or unusual noises, all seems normal.

All temperature probes appear to have valid, expected values.

At a complete loss. Is one of the flappers broken, based on previous tests cannot pinpoint any failure. What am I missing? Appreciate the feedback and hopefully a lively discussion.

 

@Greggo Many members here have experienced that same problem. I do not recall all of their remedies. Please search the forums.

 

I have been searching for a couple of weeks already and could not find anything relevant to my situation. donpb, If you can point me to a thread or post that might help, appreciate it.

 

I made a couple posts with the same or similar issue you're having. The first time it was my valve and the second time it was my aux pump. I don't know if you have an aux pump but I'd check that out.

 

Valve replaced, no AUX pump on this car.

Have run through the bleed procedure a dozen times. Head scratcher.

I am about to pull the trigger on a new controller, perhaps it has lost its mind. Easy enough to replace. Not even considering dismantling the entire dash, without hard evidence it has to be done.