Anyone speak BMW e39 HVAC?

I made the mistake of asking on bimmerforums. Ouch. Zero replies in 125 views.

Here's the problem:

2001 e39 525iT w/ the 3 knob type heat/AC controls. Evidently this is incredibly rare - every car got the more complicated automatic controls w/ multiple stepper motor controlled diverters and flaps on the heater box.

Everything works except the vents that direct air into the driver+passenger side foot wells.

There's a fluid solenoid valve under the hood with 1 in-2 outs, but the issue is air, not hot water.

I'm fishing to see if anyone has encountered this or has any advice before, armed with the 2 volumes, each 2-1/2" thick of Bentley manual that arrived today, I disassemble the entire dash.

Sorry, can't help. Ours has the automagic setup where you set your desired temperature for two zones - but you still have to turn the AC on/off manually. Weird.

I wonder if your setup might have been more common on the 3-series, and you could find information there?

Do you have the Bentley for it? I can see what it says about that...

I don't know anything about the manual climate control on the E39, but if you haven't already, try asking on the General Mechanical Help subforum on Bimmerforums. That's where most of the pro techs hang out - you've got a better shot of a real answer from one of them.

You have a rare control for sure. Assuming that setup uses cables I would start by pulling the three dial panel and checking the control cables, if the one feeding the footwell flap is slack or disconnected you'll know where to go.

Good luck finding any decent repair info for a heater. I've yet to find a manufacturer that tells you any more than how to remove the heater core. 200 TSBs about odor from the A/C, but try to figure out what door does what...

Sounds like a look see into the guts of the system might be in order. The upside is it sounds like you have cable based system so diagnosis should be straightforward. You up for documenting your progress in photos here?

realoem.com? They have diagrams for the manual a/c. Sometimes the bowden cables come adrift from their anchor points and won't move the flappers directing air. Had to add a screw for the e36...

I recommend thicker socks.

Holy crap. The e39 Bentley manual is 2 volumes, each about 2-3/4" thick.

Volume 2 is electrical, and the last 2"+ is all wiring diagrams.

The HVAC system is covered in depth, and I had to read it 4 times before I caught the buried sentence about how the "IHKR" system (the rational, simple one on my car) actuates the air proportioning via BMW's beloved "Bowden cables".

Hot damn!

So I'll pop the control panel out and see what's up.

BTW - the manual also states that "IHKA" was standard from the '00 on. So my car gets more rare by the minute. It appears the only options ticked were:

• The nice looking 2 piece BBS wheels.
• Sport/lowered suspension.
• Auto-leveling.
• Cold weather package.
• Manual trans.

In other words, what I'd have bought if I'd been the me I am now in 2001 and had $45k to drop on a car.

Bentley's slightly off on the end date for manual climate control in the E39; it was 9/01. The 2001 525i was a bit of an oddball - see here for specifics: Official BMW document

In reply to 02Pilot:

This is just what I needed, thanks!

FYI - in the off chance some poor bastard ends up here in the future with this problem.

The automatic control unit was called IHKA - the manual knob version IHKR.

The definitive guide to e39 changes and IHKR

Resolution:

Footwell flap actuation cable was detached from the back of the control panel. Required about 10 minutes to remove the panel, reattach the cable and put the panel back.

I'm so glad the original owner ordered such an odd car.