Cabin fan relay issues

A little over a month ago the heating and cooling system in my car stopped working. I had assumed the blower motor went out and just had been riding with my windows down to combat the heat.... that is until yesterday when I was driving and it mysteriously kicked on and started blowing air again. I turned on the a/c and it worked too. Everything seemed back to normal until I parked the car and turned the key. The fan would not stop blowing. Now I have to disconnect my battery every time I park. Also even when I try to manually turn off the fan when the car is running it will not shut off.

I have little knowledge like this about my car so anything will help. From my best understanding it seems like maybe I have a sticky relay? Where would that be located and what is the actual name of the part I am speaking of?

It is a
2002 530i

Any help appreciated, thanks!

No relay in this circuit. The FSU (final stage unit) controls the cabin blower motor. I've relpaced mine a few times until BMW re-designed them to have more cooling fins so they don't burn out.
It can be replaced in <20 min if you have done it before. The new style is on the left in the attached pic.
It's located on the pass side (US) up under the dash, assessed by removing the lower glove box panel and the side piece on the tranny tunnel hump. I'm sure there are tons of DIY posts. After you pull off the 2 pieces look for a connector ahead of the center HVAC box, that is what plugs into the FSU.

And use ONLY BMW brand!
No aftermarket for this part.

This same exact incident happened to me today; it blew on high for a few minutes after I turned it down to low. Now (three hrs later), on my way home the fan does not engage whether its heat or cold. Driving around FL in June is not too comfortable without air. I'll be going to BMW tomorrow to purchase the part, any ideas on the price? I can't see spending $300+ on labor for something I can easily do on my own.

Originally Posted by jjr1988

any ideas on the price? I can't see spending $300+ on labor for something I can easily do on my own.

The last one I purchased about 4 years ago was about $60, I wouldn't be surprised if it is $100 or more now.

Originally Posted by JimLev

No relay in this circuit. The FSU (final stage unit) controls the cabin blower motor.

Hi Jim,
If there's no relay, then I'm confused for two reasons.

One, is this set of videos I took recently, with clicking sounds (as if it's a relay), which were solved by removing the FSU fuse F76 and/or the FSU itself:
- One users experience diagnosing parasitic dead battery overnight current drain (1)

Originally Posted by mbell666

see this 30-second video taken a little while ago when I returned from an errand and started checking the parasitic drain again.
All of a sudden, the active current began fluctuating between 2.27 amps and 11.53 amps!


Here are those same clicking sounds, about every 3 seconds, taken from the cockpit just after the video above (they seem to be coming from behind the MID but I can't really be sure).

The second reason is that there is apparently a "blower relay" behind the glove box:
- > E39 (1997 - 2003) > Picture & amperage & description of every single fuse & relay in the BMW E39K4 = interior heater blower motor relay (1)


So I'm confused whether there is a blower motor relay or not!

Bluebee, I was responding to the other persons question, his car does not have a relay.
The pic you provided is from a car that has the IHKR heater controls, 3 knobs.
This setup does have a relay that switches 12 volts to the FSU when the blower motor is requested to run.
The newer IHKA unit doesn't use a relay or bowden cables like the IHKR.

Originally Posted by JimLev

The newer IHKA unit doesn't use a relay or bowden cables like the IHKR.

Ah, I see. So, my 2002 must not have a blower motor relay.

I need to update this thread:
> E39 (1997 - 2003) > Picture & amperage & description of every single fuse & relay in the BMW E39

BTW, does that high amperage clicking sound in my videos above sound like anything familiar to you?

If you have the the IHKA you don't have a relay.
Not sure what the clicking sound is coming from.

Originally Posted by JimLev

If you have the the IHKA you don't have a relay.

Ah, thanks for clarifying.

Originally Posted by JimLev

Not sure what the clicking sound is coming from.

Me neither!

is hitting on some dirt. There are grilles on the left side of the climate control unit.Some of them are open some are dummies. Try spraying some electronic contact cleaner in open grills with heater /or AC on. It stopped the noise I was getting. Others have opened the unit to clean out fan, but that was too evasive for me and easier way worked! Radio shack sells it.

Originally Posted by jygesq

is hitting on some dirt. There are grilles on the left side of the climate control unit.Some of them are open some are dummies. Try spraying some electronic contact cleaner in open grills with heater /or AC on. It stopped the noise I was getting. Others have opened the unit to clean out fan, but that was too evasive for me and easier way worked! Radio shack sells it.

Sorry, but I have no idea what location and what 'grilles' you are talking about (if this is directed to me).

If it's directed to the OP, please ignore this post.

Originally Posted by bluebee

Ah, thanks for clarifying.


Me neither!

buttons for setting temp for both sides of the cabin. just below them there are grilles or slots. THe ones on the right side are dummies. Some of those on the left side are open. I usually use a tooth pick to clean junk that gets caught in the slots that are open. You can spray electronic contact cleaner through the left sided ones that are open. I cleaned the internal fan in the climate control unit that way and eliminated noise .

DO you men the grill under #3 and #4 in this picture below?

yes the grills under #3 & #4 , in fact you can dirt in #3. Try it you have not much to loose by cleaning it out with spray contact cleaner. Remember grill #4 is a dummy it has no openings.

Originally Posted by jygesq

yes the grills under #3 & #4 , in fact you can dirt in #3. Try it you have not much to loose by cleaning it out with spray contact cleaner. Remember grill #4 is a dummy it has no openings.

I would take the IHKA panel out, open as much as I can, then use unly compressed air at low setting.
I too used contact cleaner after first blowing with air only, and after a few weeks the IHKA panel went dead. Maybe it's coincidental, but I will never use the contact cleaner blow-in method again on the IHKA panel.

0.02

Originally Posted by jygesq

yes the grills under #3 & #4 , in fact you can dirt in #3. Try it you have not much to loose by cleaning it out with spray contact cleaner. Remember grill #4 is a dummy it has no openings.

Wow. That's INTERESTING!

That is my grill there - and they 'are' dirty - and - well, I never knew (or realized) that the right-side grill is a dummy.

Thanks for adding value!

EDIT:

Originally Posted by doru

I will never use the contact cleaner blow-in method again

Ah. I see. OK. So I'll use a soft cloth and a can of compressed air instead. Thanks for the warning.