Heater Blower and Rear Window Defrost NOT WORKING

[BimmerJack]

I have a 95 525i VIN is WBAHD6320SGK54516. It was an intermittent problem that I think is now permanent. I do not have any air flow in any of the 4 positions and the rear window defrost is not working. Are these two functions electrically tied together somewhere? Both fuses look OK. I did have a microfiber filter that I removed and decided not to replace it after all the trouble getting it out!! Need some ideas...there's still plenty of cold weather left in the Denver area! LOL

Jack

[shogun]

Well, have you checked all fuses and the relay?
Here is the system
http://www.bimmerboard.com/forums/posts/145262/
no blower fan?
http://www.bmwe34.net/e34main/maintenance/electrical/sword.htm

wiring diagrams where you find the fuses and relays
http://shark.armchair.mb.ca/~dave/BMW/e34/

[BimmerJack]

Thanks Shogun for all the reference material and I will check it all out. But is there anything that would make both the heater blower and rear window defrost operate/and not operate together? When they work, they both work. When they don't work, both are out.

[shogun]

both are controlled by the IHKA module.
Integrated Heating and Cooling Automatic.
That is located in front of the heater core, 2 connections on each side, that means 2 on driver side, 2 on pass side.

white connector X610 'A'
1-4 stepper motor fond area
5 heater sword
6 aux fan
7 rear window heater relais
8 climate control relais
10 NC
11 NC
12+F20 (30)
13+F20 (30)
14 - 17 stepper motors for air distribution (recirculation)
18 light switch LED
19 light switch LED
20 TXD
21 water valve left side
22 aux water pump relais K8
23 water valve right side
24 front window heating relais K8
25+F20 (30)
26+F20 (30)

Blue connector X613 "C"

Pins are in such way
13 up to 1
26 to 14

1= ground
2=ground
3= NC
4=temp feeler driver side
5= potentiometer blower motor
6= temp feeler in engine room
7=outer temo feeler
8= potentiometer temperatur driver side
9=NC
10+,11+, for stepper motors
12+F21 (15)
13+ F21 (15)
14= ground
15=ground
16= potentiometer+ feeler ground
17= potentiometer flappers
18 temp feeler left
19 starter (50)
20=potentiometer+feed
21 temp feeler inside
22 temp feeler reight side
23+ for stepper motors
24+for stepper motors
25+26 = F21 (15)
26+ F21 (15)


green X611 „B“
1 to pin 14,15,16
2,3,4,5 mixing flap motor left
6,7,8,9 fresh air stepper motor outside
10 NC
11 NC
12 NC
13 NC
14, 15,16 with pin 1 legroom stepper motor left
17, 18, 19, 20 defrost flap stepper motor
21, 22, 23 fresh air stepper motor left
25 NC
26 NC

yellow connector 614 „D“

1,2,3,4 legroom stepper motor right
5 MPX button
6 MPX button left
7 MPX defrost
8 MPX button right
9 speed signal
10 RDX
11 button rear window defogger/defroster
12 MPX button recirculation
13 MPX button aircon
14, 15, 16, 17 fresh air stepper motor right
18, 19, 20, 21 mixing flap stepper motor right
22 NC
23 NC
24 NC
25 NC
26 NC

The connectors are:
13 12 11 10 9 8 7 6 5 4 3 2 1
26 25 24 23 22 21 20 19 18 17 16 15 14

See the connectors, they are marked with small numbers outside

http://bmwe32.masscom.net/johan/ihka/control_unit_1.jpg

the SWORD has a 5 pin connector

Pin 1 connector for the potentiometer for speed regulation at the control panel.

Pin 2 power supply

Pin 3: the relay get's contact when the blower fan potentiometer is adjusted, 12 volts come on.

Pin 4 is ground

Pin 5 the cable/wire from the blower fan.

Remove the plastic covers from the sword and connect it again to the control panel.
Use a multimeter to test it.
When you turn the thumbwheel at the potentiometer, the voltage at pin 1 changes from 1.1 - 4.25 volts. As the transistor, which amplifies the potentiometer, only has a voltage (input) of 5 volts, that should be the full power of adjustment.

In case the blower fan only starts at let's say 3.5 volts then the pre-amplifier IC (I think it is IC LM 139) is defective. There are 2 pre-amps installed. Cost around 2 $ if you do it yourselves.

[BimmerJack]

I didn't think a 95 had a "sword" based upon the first info you sent me??

[shogun]

Ohh sorry, I was mixing up with the E32.
So forget about the sword.

[BimmerJack]

Does the lack of a sword change things in your description above?

[shogun]

not 100% sure. But you can check it by yourselves for the E34, took me "only" some hours to find out all the connections for the E32 in the wiring diagrams.
http://shark.armchair.mb.ca/~dave/BMW/e34/

[JohnC]

Is your resistor pack ok?

[BimmerJack]

Please explain? I've read a few things about this part, but haven't had a chance to investigate it yet. Would a bad one cause both the heater blower and rear window defroster to stop working? How do you test it to see if it needs replacement? Thanks in advance...Jack

[JohnC]

If you don't have a sword you have a resistor pack. I know it does something with the fan's speed but I'm not sure about the defroster. Its less than 20 dollars and really easy to swap out so its worth a try atleast.