Air Conditioning Problem

[Islandhopper]

Hi Everyone,

I have a 1997 BMW 318i with about 110k miles on it. The AC was working perfectly and just suddenly stopped working this week. I checked the compressor and it is still engadging and turning fine. Also, the light on the AC control panel still comes on, it just doesn't blow any cold air at all. It didn't gradually die either, it was sudden.

Any ideas what this could be?

Ryan

[randomy]

aux. (pusher) fan failed perhaps

[Gene1219]

Get a pressure gauge to test how much psi your system has.

On a side note, with the lcd climate control, do those go bad?

[delmarco]

On a side note, with the lcd climate control, do those go bad?

They are known to go bad and not be all that reliable

"Suddenly" sounds like a FUSE blew. Check your fuses.

[Islandhopper]

aux. (pusher) fan failed perhaps

It blows hot air, just not cold air... so it's not the fan.

[pordway]

I had a problem with my 1997 328i AC it would work and not work and then work. There are quite a few places onthe internet that will rebuild the control unit (if that's the problem - mine was) for a reasobable price. Search BMW Air Conditioning

[mpwr ren rebel]

I'd say check fuses and pressure like the other guys have said.

Since we're on the subject of A/C, I have (what I think is) a minor problem with mine. It'll blow cold air just fine. Then randomly stop blowing air (doesn't happen too often). Then a few seconds later, it comes back and all is good. The air isn't as cold as I think it should be. Anyone know if this could be a sign of low pressure? Or what?

[328 Power 04]

I'd say check fuses and pressure like the other guys have said.

Since we're on the subject of A/C, I have (what I think is) a minor problem with mine. It'll blow cold air just fine. Then randomly stop blowing air (doesn't happen too often). Then a few seconds later, it comes back and all is good. The air isn't as cold as I think it should be. Anyone know if this could be a sign of low pressure? Or what?

you have the problem with the transistor inside the climate control computer, it needs to be re-soldered

[mpwr ren rebel]

you have the problem with the transistor inside the climate control computer, it needs to be re-soldered

Doesn't sound like fun. I always thought there was a funny noise coming from the climate control unit. Is there any write up's on it? I've never read/heard about the digital units going bad. Is it uncommon?

EDIT: Found this: http://www.macadamizer.com/bmwfix.html Do I have a problem with a transistor or capacitor? They are different, aren't they? What capacitor size have you other guys used?

[Islandhopper]

you have the problem with the transistor inside the climate control computer, it needs to be re-soldered

Would that be the same problem I have? The compressor is turning ok, all of a sudden no cold air coming out, just warm air...?

Ryan

[enabled]

Yeah, i have problems with my a/c too. My heat works just the a/c gives me problems. The compressors fine, i guess the aux fan is fine too, fuses are fine, the low side hose was replaced within the last year...but it just dont blow cold air...that long anyway.

Ill go to fill it up with some r134a and it blows cold for about 2-3 weeks. anyone have any idea on the problem?

[choffa]

A refrigerant leak should be located & repaired. If it is on the low side, there is a possibility that air may have been pulled in (after all of the refrigerant leaked out). Only solution is to evacuate system to remove air, repair leak, change receiver/dryer & recharge. Air is considered "non-condensible" and will adversely affect the cooling capacity even in small quantities.

[duce110]

just being curious here, but under the vents there is a lil wheel that u can turn and the main vents will start blowing out hot air and the passenger side by the door would blow out cool air... if u turn it the other way, it changes to cold air, that maybe ur problem, maybe moved it by accident... i know cause it happened to me...

[Islandhopper]

Nah, that definitly wasn't it.

I just added 2 cans of R134a, took me awhile to find the LP port which happened to be on the firewall..the HP port was the one above the RH headlight.

Now we'll see if it holds... at least this was a quick and dirty troubleshooting technique if nothing else.

[johnnyb395]

I had the same problem. The AC works but blows hot air. after I checked and played with everything it turned out to be the Heater control valve it is mounted on the engine side of the firewall driver side. It is easy to test, with the AC running and the temp outside higher than the inside you will be able to feel the rubber lines as very hot. If you have a IR thermometer it is even easier. The default for the climate control (if it goes dead is to not supply 12v to those valves (wide open). they it is a pain to replace. No need to drain the system you will loose little fluid.

[johnnyb395]

Just thought of something else. I know that others have mentioned the climate control module. If it is not acting erratic don't worry about it. Unfortunately it will fail soon. If you are good at soldering ( i mean you have been an electronic tech) then get yourself a 220uf/35v pc mount electrolytic capacitor. After you take the unit apart you will see that the wrapping on the cap has shrunk a sure sign of a bad capacitor. Your current problem will be the Valve

[ponchiz318]

Another thing to check, if you have to replace heater core, evaporator, condenser, etc. Check the line filter. Inside the rubber hoses, there is a filter that filters out any debris that may be in the system. Over time, you do get debris. When this is clogged up, it does not let freon to pass through properly, which in turn the air is not as cold. It's a 10$ filter but I must say, if you do not have experience with working on A/C's then try and find someone that would teach you. Or look it up on the internet if you really want to do it yourself. There are certain things you must look for while doing this. First, you must vacumm out the system by plugging in a special vaccumm that is designed for the A/C. This will relieve it of any pressure that is in the system. You must have the guages in order to do this. Suck everything out for about 10 to 15 minutes. The guage should be around -5 to -10. After that, you must pressurize the system with air or prefferably, nitrogen. Air has too much humidity. Nitrogen is really dry. The humidity can later cause rust within the system. Thus clogging your system again. You will charge the system to about 150psi. Check for leaks by using a spray bottle with soap and water. Check for air bubbles of course. Also, check your compressor. I have seen plenty of "new" looking compressors that leak from the clutch. If it's leaking there, then you need a new one. If it is leaking from any connection, i.e, hoses to the compressor, hoses to the evaporator, to the condensor, etc, etc, then it's a simple o-ring. Let out the pressure, change the o-ring, put everything back together, get your R-134 out and begin pressurizing. The compressor should never be pushing out over 300psi. That means that it is faulty.
If I get a chance, I think I'll do a full write up on this, I just figured out that I have typed so much. It's relatively easy, but there are things you must check for all the time.

[trwpass]

No lights on the panel and nothing happens when I hit any of the buttons. Checked and it appears all fuses are good. Any suggestions?

[RNeil]

you have the problem with the transistor inside the climate control computer, it needs to be re-soldered

It sounds like the capacitor needs to be resoldered. Do a search on "capacitor". I have not heard of problems with climate control transistors. There is a very explicit write up on how to do this. But the write up says to replace the capacitor. Others have found that it only needs to be resoldered, which is easier than replacing. I got a replacement at Radio Shack for about $2.

I always thought there was a funny noise coming from the climate control unit.

There is a very small fan that blows air accross a temperature sensor. It runs a short time after you turn off the car. I don't know why.

[rajeshpai2004]

The expasion valve was replaced and gas was recharged and the aircon was very effective. After two months started to blow cold/chilled air from the vent on the drivers and passenger side on the dash board. At the same time very hot air is blown from the floor level vents.
Any suggestions to the problem....

[choffa]

Same thing here. Search for a recent thread on repairing the heater control valve. Most likely it is stuck in tthe open position. I have yet to pull the valve but the thread is very well written. Pelican parts website technical section also has a diy.

[paniolo]

The expasion valve was replaced and gas was recharged and the aircon was very effective. After two months started to blow cold/chilled air from the vent on the drivers and passenger side on the dash board. At the same time very hot air is blown from the floor level vents.
Any suggestions to the problem....

This sounds like your heater control valve has gotten stuck open. So in effect you are running the a/c and the heater at the same time. Pelican Parts DIY on heater control valve.

[heartin]

Your problem can be solved only by an expert. Take the advice from atleast five experts to have a better solution of your problem. visit
Hialeah Air Conditioning

[avalenzuela]

My 2001 540i is acting weird. Got up this morning went in the garage and it sounded like an airplane outside. Its was a bird a plain!! NO!! It was my car!!The A/C blower was on and my car was off!! I opened the door tried to start the car and the battery was dead. I jumped it and could not turn off the A/C cause the panel did not work and no lights on the panel lite up. I searched for the problem on the internet and found out that it could be the blower final stage fan resistor. But it did not say anything about the A/C controls not working. So I dont know if it is the FSU or not. Any have this problem or know what it is.

This is my first time logging on to this forum, so hello everyone.

I appreciate your help.

Thank you and have a wonderful weekend,

[flyfishvt]

This is the e36 forum. You have an e39. You will get much more accruate answers in the e39 forum.

Just to touch on your issue...On digital climate controls...when the FSU goes bad the fan wont run at all or it only runs on very very low speed. The rest of your problem may be something common to e39's. Go to that forum and start a new thead.