Odd (for me) Climate Control Malfunction

[McLovin]

So I have a problem with my climate control that I have never seen before. Car is a 2001 540i Sport with 284,500 miles. I have had this car for over 8 years and have done all my own work. Normal stuff that we have all had to deal with to own one of these fine cars. What occurred recently has me stumped and a search of the archives here does not seem to yield exactly what I am looking for. The problem:

Upon starting my car a couple days ago the blower begins to blow on its highest setting. I look down and the entirety of the climate control is dark. No display at all is showing on the faceplate. None of the buttons work and i cannot shut the blower off or down. Make matters worse, the fan is blowing hot air. Hot air on the hottest day of the week here in Virginia. I have to get to work so i suck it up and keep driving. I get to work and shut to the car down and the blower will not shut down. The only way to shut it down is to remove the negative battery cable. I come back out a few hours later and put the battery cable back on and the blower starts right back up on high with the car still shut down.

Since I have replaced the FSU at least 3 times since owning this car I always have a brand new spare in the trunk. 10 minutes and I have a new FSU installed. Re-hook up the battery and the blower still comes on and the climate control unit is still dark. In the little time I had before I had to travel out of town I checked the fuses and they were all ok. But the only fuse bank I have checked is the one in the glove box.

So I am kinda stumped. Any ideas before I get on ebay and purchase a used climate control unit?

[StephenVA]

I am interested in this issue as well and would welcome anyone's diagnosis process. In the research I have found the issue lies in the HVAC module or the control head itself. I will pull some codes and let you know what I see.

The blower, you can pull the fan fuse and it will stop. Downside: the HVAC system is on HEAT so when you drive you get air flow through the heat side and you will TOAST ALIVE. Not a fun ride in our heat.

[crazy4trains]

Keep us informed if you are able to resolve.

[BimmrMeUpSnotty]

Stratification knob doesn’t do anything from red dots to blue? Might at least switch the gates to the cold side.

[edjack]

My guess is a bad IHKA panel.

[McLovin]

The hot air blows exclusevely from the floor vents so i did not consider the stratification knob as an issue. Regardless, there is still be problem of the blower not shutting down when I shut the car down and remove the key.
I just popped the climate control unit out of the dash and checked the plug connections. All seemed good, but that did not fix the problem.

I'm thinking it is a bad control unit and i will have to replace.

crap

[edjack]

That's what I suggested.

[BimmrMeUpSnotty]

Should not need any coding to pop another one from another car, should it?

[McLovin]

I would not think so.

[Qsilver7]

Should not need any coding to pop another one from another car, should it?

Not as long as it is like for like. If you have the REST button and try to install one with the MAX button...then your software will not run the pre-programmed MAX settings...and you probably don't have the solar sensor either...which also affects the IHKA's operation.

If you have a REST IHKA...then replace it with another REST IHKA. If you have a MAX IHKA...then replace it with a used MAX IHKA to not have any issues.

{IHKA w/MAX button}




{IHKA w/REST button}

[Flounderasu]

As Ed an Q state, you need a new IHKA panel

When the panel dies, you can't control the vents that change from recirculation to letting airflow from outside and defaults to the outside airflow even if the panel died in Recirc mode.

[BimmrMeUpSnotty]

Not as long as it is like for like. If you have the REST button and try to install one with the MAX button...then your software will not run the pre-programmed MAX settings...and you probably don't have the solar sensor either...which also affects the IHKA's operation.

If you have a REST IHKA...then replace it with another REST IHKA. If you have a MAX IHKA...then replace it with a used MAX IHKA to not have any issues.

Oh man, that’s right. Forgot about the two different types! Both of my E39’s have the REST IHKA’s.

[McLovin]

Well, it is off to ebay i go to purchase a used panel. Mine is the one with the Max button. I kinda figured I would need to get a new unit. I was hoping all of you would know some super secret BMW fix that I was not privvy to. Oh well, thank you for the feedback. I do appreciate it.

[JimLev]

The HVAC panel controls the 2 valves and aux pump that are mounted low on the drivers side strut tower.
When the valves aren't powered they are open which is why your getting heat.
Pinch off the line from the engine to the pump should stop the heat.
The whole assy will pull straight up out of it's mount, no tools needed.
Disconnecting the cables on the back of the HVAC panel should stop the blower motor from running.

[dannyzabolotny]

My friend had this exact same issue with his 2002 540it, he replaced his IHKA and that fixed all the problems.