What part is this?

[Alpinewhite]

What is the part which says 01 UNCODED CONTROL UNIT F AIR CONDIT

http://www.realoem.com/bmw/showparts.do?model=HE23&mospid=47406&btnr=64_0168&hg=64&fg=45

My local says I got to change this one for my AC to work. It is really costly, I want to make sure it is this that I have to change and not some stupid sensor. Any one know what this does and why it is $$$$$?

Thanks
Arun

[Kalevera]

Final stage for the blower motor -- a collection of resistors that typically goes bad over time (do a search on "sword" and "resistor pack" -- two different variants found depending on model and year). Relates more to fan operation than A/C efficiency.

Where are you located, what is the car, and what is it doing?

best, whit

[Alpinewhite]

Thanks for the response. Just making sure there is no misunderstanding. My local says my car requires AC control unit which is labeled as 1 in the diagram (P NO 64118367951) not the one which is labeled as 2 "limit switch"

http://www.realoem.com/bmw/showparts.do?model=HE23&mospid=47406&btnr=64_0168&hg=64&fg=45

I am located in Atlanta area. My car is a 1995 530I. My problem: When I switch on the AC it stays on for less than a minute and switches itself off (Light in the AC button goes off). After that the car itself would try to switch on the AC for every 1 minute (You can hear the engine revving up to 750rpm for a moment) but the light in the panel wont glow.

Thanks
Arun

[Kalevera]

Sorry, I'm dyslexic sometimes. Is the system holding pressure? It probably is, but if you're trying to cover the bases, that's the first one to round.

best, whit

[Alpinewhite]

Yes it does hold pressure. Where to look at next? I am really not convinced that my AC control unit is gone.

A question to all: What are the things that have gone wrong in your e34 AC system? your answers could probably save hundreds of $$$

Thanks
Arun

[632 Regal]

it holds pressure so have it checked and filled, if its low it could cause strange things.

[jjdickm]

my 1990 525i did that also then it completely would not work I replace the sword resistor and it works again.

[Alpinewhite]

I did fill it. My car takes 3 and odd pounds. My local filled it full.

You know the wierdest thing: My local has a diag software and he hooked up a computer and he was able to switch on AC with it. AC was blowing air with 42'F.

Thanks
Arun

[JonE]

Gee, I don't believe the issue of part #1 has ever come up here before, please keep us posted on this one. Perhaps it can be accessed and cleaned up or something? Should be in the vicinity of the microfilter stuff. I'd take a look in there and clean contacts, etc. first.

[Alpinewhite]

I thought the sword is only to control the fan speed. Did the fan work in your case?

Thanks
Arun

[JonE]

Typically sword failure presents as either no or intermittant 1,2,3 fan positions but works fine on "4". I believe others have experienced some other behaviors with the sword as well.
When my AC wasn't working, it was low on freon. I believe you can also have issues if the system is over filled. Just another thing to consider...
I'd still get in there and check the sword/microfilter/part #1 area for myself.

[Alpinewhite]

I will clean those contacts this weekend and see.

According to my local The worst thing about this AC control module is that it is programed for each car. Because of this I cant take it from another parts car and put it in my car. I dont understand why would they program it for each car - for security reasons?

Thanks
Arun

[nk530]

When my AC wasn't working, it was low on freon. I believe you can also have issues if the system is over filled. Just another thing to consider...
I'd still get in there and check the sword/microfilter/part #1 area for myself.


make sure you don't overfill your refridgerant, you can slug the compressor and end up replacing that, too.

[Alpinewhite]

Guys,

Thanks for your responses

But Is that all that could go wrong in the AC system?

So far I have heard:

1. Low refrigerant
2. High refrigerant
3. Sword - I dont understand how this directly afects working of AC
4. Thermal switch in the compressor (if applicable)

Please add all the problems you faced in AC and got fixed. It will be highly helpful for me to trouble shoot.

Above all if someone knows / has a guide to trouble shoot AC system in 1995 530I please let me know.

Thanks
Arun

[Rustam]

What is the part which says 01 UNCODED CONTROL UNIT F AIR CONDIT

http://www.realoem.com/bmw/showparts.do?model=HE23&mospid=47406&btnr=64_0168&hg=64&fg=45

My local says I got to change this one for my AC to work. It is really costly, I want to make sure it is this that I have to change and not some stupid sensor. Any one know what this does and why it is $$$$$?

Thanks
Arun

Is this a trick question?

This is a module that has resistors in it. Shifting from one position to another on blower control engages resistors in this part that make the blower work at desired speed. You may want to try to open the original one since it doesn't work and peek inside - perhaps the resistors can be changed?

[BillionPa]

its not just for the AC unit, it controls fresh air ventilation and a good chunk of the heating system too. it is in fact just behind the microfilter and has a massive amout of wires plugged into it, more than the ECU!

there are IC chips in there and any sort of leak from the microfilter area or ac evaporator would likely corrode the hell out of the unit. mine is beyond repair.

if you can get to the unit, after removing the glove box/center console etc, take a look inside. if there is corrosion replace it, but you CAN get some of these units on ebay or from a junkyard for about $100, vs the $500 or so a new or reconditioned one costs.