Subject: More IHKA problems...Help, I'm FFFFreezing (long-ish) Author: bimmermeister : member since May, 2007 : 182 posts Posted on: 2008-01-21 21:47:55

Symptoms: no heat flow from upper or lower vents after driving the car 30 or more minutes on the highway. I can hear the fan/blower and it responds to the fan speed control from low to high, but no air flows from vents and only a little from the defrost/demist when activated. Previously, when I replaced the IHKA control module near the "sword" and had the dash side panels out, I was able to observe the lower air flaps responding to the mode buttons.

Previous owner replaced heater valve with salvage unit. I tried unplugging the two-wire plug at the valve with no improvement. What is the three-wire plug for and should I disconnect that also? De-fault should be full heat/coolant flow to heater core, right?

What I've done:

1. swapped IHKA control panel from 1/91 board to ?/88 board (re-flowed solder joints on the ?/88 board)
2. Swapped IHKA module with another of close serial number (visually inspected solder joints on the replacement IHKA board and they looked good)
3. replaced thermostat, gage reads in the middle of the range
4. Replaced cabin/micofilter last July, removed and cleaned with
compressed air in the last two weeks.
5. re-flowed solder joints on original IHKA control panel circuit
board (no improvement)
6. re-flowed solder joints on original IHKA module circuit board
(no improvement)

Where do I go from here? Should I replace the "Sword"?

Occasionally I can hear the fan speed slow or shut off then re-start, but when I notice the lack of heating the most, I can hear the fan running. The sword only controls the fan speed and not the air flow right?

Mark, freezing in Colorado



1991 750i DC05875 Mfg. 1/91, Euro model from the Fatherland

• More IHKA problems...Help, I'm FFFFreezing (long-ish) - bimmermeister 2008-01-21 21:47:55 (176 views)
  • Re: More IHKA problems...Help, I'm FFFFreezing (long-ish) - akneppers 2008-01-22 18:15:14 (117 views)
  • Hmmmm... - kharon8 2008-01-22 04:25:04 (130 views)
    • I'll go and see mine, pictures later.... (nt) - kharon8 2008-01-22 04:26:23 (84 views)
      • ... and here they are. (pic) - kharon8 2008-01-22 09:24:05 (686 views)
        • Tuomas, yours are the version for parked heating system? - shogun 2008-01-22 10:19:03 (110 views)
          • How exactly are they different, Shogun? - steinway 2008-01-22 16:50:41 (91 views)
            • I am not sure, never have seen older one - shogun 2008-01-22 17:39:13 (88 views)
          • Yes, it is. (nt) - kharon8 2008-01-22 10:27:48 (68 views)
            • pics of repair and cleaning of aux water pump (url) - shogun 2008-01-23 04:42:45 (154 views)
              • Am I? Ouch. - kharon8 2008-01-23 04:57:28 (77 views)
                • Registered now, good pictures. Thanks. (nt) - kharon8 2008-01-23 05:10:10 (66 views)
        • Pre- pressure hole it is. - kharon8 2008-01-22 10:01:40 (97 views)
  • just had a similar problem on my E31 - Rich 1990 750iL 2008-01-21 21:58:10 (114 views)
    • Re: just had a similar problem on my E31 - bimmermeister 2008-01-24 23:43:10 (102 views)
    • 2 wire plug is for the aux water pump (url) - shogun 2008-01-22 00:34:26 (145 views)