Automatic air conditioning

arthur · 07-18-2003, 05:43 AM

Hi All,

My automatic a/c comes on intermittently and I have searched numerous sites about this fault. All of these sites have pointed to the blower resistor component as the probable cause. I have a uk bmw 323ise 97 model (right hand drive) and am not sure where exactly this is located.

I would appreciate it if someone could tell me where it is located (diagrams would be very useful) and how to fix or replace it.

Thanks

matthew-m · 07-18-2003, 07:10 PM

This must be a common problem because the same thing happens to me on a USA 97 328i. I'd like to fix it before I move out to the desert and I'm stuck with out A/C!

arthur · 07-26-2003, 01:05 PM

I think I've finally fixed my a/c problem.

After a week or so searching for the blower resistor, taking both the glove compartment off and the panel in front of the drivers seat and pulling serveral small parts out, I decided to take a fresh look at the problem in hand.

It wasn't long before I came across the web page http://www.macadamizer.com/bmwfix.html and immediately established the problem was in fact with the climate control unit. Following the instructions from this web page, I was able to replace the faulty capacitor on my unit and now it seems to be working again.

A point of advice for anyone else who tries this, buy a couple of capacitors or make sure it works properly before you put it in because the first one I put in didn't work and then I tried again and the second one did work.

In total I spent £7.50 for the soldering tools and 24p for the two capacitors that I bought (The cheapest repair ever on my bmw and I did it myself, Wow!).

kingnine · 07-26-2003, 06:41 PM

Sometimes you don't even have to replace the capacitor. I just re-soldered the capacitor terminals and it worked perfectly.

arthur · 07-29-2003, 02:04 AM

Just when I thought everything was back to normal my a/c is playing up again. This time the blower heater and a/c will run for about ten minutes and then shut off. I don't think the fault is with the climate control unit as the lights operate when I press the buttons and I can hear the internal fan as well.

Anyone know what could be causing this?

Thanks

EXtech · 07-31-2003, 04:48 PM

Is this after you turn the vehicle off? Or when you turn on the system, does it work for ten minutes and then cut out? The capacitor, think about it's purpose and design ....... it stores a charge. Most likely what's happening is that there is a dormant charge stored in the capacitor, then when you eliminate power from it's normal source (shutting the system off) then it sucks the power from the capacitor until drained. What do you think? Do you think it applies?

arthur · 08-01-2003, 03:03 AM

This is very possible. The system works perfectly fine at all blower speeds for ten minutes and then the blower shuts off, although the lights on the control unit operate and the demister works. It will then not work for the next ten minutes and then start up again recursively.

Its as though something is getting heated up (or drained in the case of the capacitor) and I don't think there is anything wrong with the blower itself.

First thing I'll do is put the old capacitor back and see if it is actually the solder joints that were causing the problem. If I need a new capacitor can someone give me a link to were I can buy one in the UK, which has been tested.

Thanks for you input EXtech

EXtech · 08-01-2003, 03:40 PM

arthur, i know this must frustrate you. According to my sister whom hails from London, the proper word here is *bollocks*!!
I would try the original capacitor and pay careful attention to the connections. Was the replacement capacitor the same specification as the old part? This can make a huge difference. If putting the original part back in doesn't work, don't be too quick to rule out the blower motor itself. I've seen those babies pull off some pretty mean tricks. Lot's of times what happens is that the final stage resistor looses it's function and resistance creating excessive current to the blower motor, which in time can eventually wear the motor out so much that it will get too hot and lock up. So then both items need replacing. I think it was in reply to your post, or maybe someone else's.. but I advised checking over the blower motor while replacing the resistor for this reason. Let me know what you find out, I am very curious...

matthew-m · 08-01-2003, 06:30 PM

I think this usually happens when the car is first started, correct? You start the car, everything works fine, couple minutes later the air stops blowing (despite being on full), and a couple more minutes later it turns itself back on. After that you can drive 300 miles non-stop and it will continue to work fine again, until it sits awhile and becomes cold again. I've had this happen for the at least the last year now, and it's getting annoying. I look forward to hearing how you solve your problem, if they are similar.

EXtech · 08-01-2003, 06:57 PM

matthew-m : have you followed the post? Was your final stage ever replaced? Give some details about what you've done or tried and what the symptoms are. Hopefully we can provide some help.

arthur · 08-04-2003, 01:31 AM

I put the original capacitor back on friday, putting great care into the soldering and yes the problem still occurred until this morning. I drove in to work (a half hours journey), leaving my air conditioner set to half its full power and it carried on working throughout the journey. Maybe the fan stops working at full power and if so I'd be inclined to leave things as they are for now. I'll be taking a look later and will inform you guys what happens.

Extech, your suggestion about looking at the blower and final stage resistor seems interesting however my original post on this thread was concerning the location of the resistor on a UK 323 model from 97 and no one came up with a reply. Do you know where it is?

EXtech · 08-04-2003, 08:29 AM

Arthur: I can't say for 100% certainty without a little investigation, but I cannot imagine that the location would be any different than a US version. It should be attached to the blower motor itself which is located in the cowling underneath the windshiedl wiper area. Some people go through the inside of the car and rip out the whole friggin dash. I always went from under the hood... it's much quicker and easier. I will try to find some diagrams for you, if not you can always email me and I will try to step you through it.

matthew-m · 08-04-2003, 10:08 AM

Extech: I have been following the posts. I haven't done anything yet because I've always felt the repair wasn't worth the effort. It only happens when the car is cold (no matter the actual temp) and only lasts about 5 minutes. I'll wait and see if Arthur has any luck fixing his, and then try mine.

EXtech · 08-04-2003, 11:20 AM

matthew: sounds like you might have something a little different, can you describe your symptoms? Maybe we can help you find a solution.

arthur · 08-05-2003, 04:23 AM

The faults still there, after putting back my original capacitor. In-fact its worse now because it doesn't come back on after it switches off.

Maybe this change in behaviour is due to the heat were getting over here right now (~100 Fahrenheit). Anyway I am going to give the capacitor replacement one last chance. I've ordered a polyester capacitor from maplin and should have it sometime tomorrow. (I found this info on another website about fixing the control unit www.bmwland.co.uk/talker/viewtopic.php?t=2780) )

I'll let you guys know how it goes

matthew-m · 08-06-2003, 09:26 PM

Extech: The blower stops running a couple minutes after starting the car for the first time (like in the morning). A/C compressor still works, heat works but the air doesn't exit the vents. A couple minutes later it works just fine and will continue to work until I let the car sit for at least 4 hours. It doesn't happen everytime, but it seems to be happening more frequently. I'm guessing this is the same problem?

EXtech · 08-06-2003, 09:47 PM

Matthew.... this is where I'd break out the digital VOM (volt ohm meter). Are you electrically incline enough and understand how to use one? If so, then get the car ready (gain access to the blower motor/final stage) so when the car is cold in the a.m. you can test it. Start everything and when the blower stops, check voltage on both sides of the resistor. If there's power up to the resistor but not out, then you have a faulty resistor. If there is power in and out and the blower motor is still not running, then you have a faulty blower motor. Make sense?

matthew-m · 08-07-2003, 06:35 PM

Sounds a lot like work to me...I'll just wait until it completely stops working and replace it then. Thanks for the info on how to find the fault.

EXtech · 08-07-2003, 06:39 PM