Hi guys, I have a problem with the A/C; some time ago I had my battery die on me; I changed it but when I went to turn the A/C on some days ago, it didn't cool the car down. I went to have it recharged as I never had it done since I bought the car in 2004 so I guessed that was the problem, but I was told I needed a new compressor.

Now, I've found a cheap one on Ebay but before buying it and going to a garage to have it fitted I'd like to run some tests on the A/C electrical system to be sure that the battery failing hasn't led to some electrical trouble (it was rainy those days and as you know when the battery fails the windows stay slightly open so I found the cabin quite wet).

What do you suggest to check? Does anyone have a wiring scheme of the A/C system?

 

Chances are that the compressor part of the compressor is fine but the clutch is bad. Rather the coil in the clutch is bad.

Check post #13 in this thread.

Here's the ebay link.

My friends are going to Germany in the next few weeks and I think I'll have them get one for me "just in case".

///Rich

 

I'd start with a visual.
Start engine, observe that AC pulley is spinning, but compressor is not.
Turn on AC.
If compressor spins, it's not your clutch.
Next, check that the low speed fan comes on. If it doesn't, you could have a bad fan resistor, or the AC is not attaining the pressure needed to signal the fan to cycle.

 

Thanks to both for your replies, I'll do the visual check and see what I can get from that.

EDIT: I was just thinking, right now my system has been emptied of the refrigerant; should I put it in again before doing this visual, or should the compressor and fan start all the same even if the system is empty?

 

Not sure if it will kick on if there's no pressure. Easy enough to try though. You'll be able to tell if the clutch is good, but you won't be able to tell if it's bad.

 

Oh well, it's a quick test anyway so it's worth a shot before putting the refrigerant back in; also, I should be able to get a definite answer on the fan at least, shouldn't I? That would be a start.

In case I wanted to check that electrical signals are correctly arriving to the A/C from the dash what should I check? I've read that there's a relay which powers the clutch, is that the only thing to check on the line between the dash and the A/C clutch or is there a fuse too?

Also, if I have a bad clutch and decided to do the work myself, how hard is the removal and repositioning of the A/C belt on the pulley? I'm scared that I might be able to take it off but not to put it back in place as I don't have the BMW special tools to do that job.

Thanks again for your help!!

 

The belt swap isn't terrible, but it's a PIA.
https://www.northamericanmotoring.co...973-post1.html
For a workaround without the BMW tool. I used a 3/4" crow bar - I wouldn't recommend it. A 1/2" pry bar is best, but many have used various and sundry pieces of metal stock.
Other threads have said that the bolt holding the pulley on can be a bear.

I didn't play with the eletricals, but there is only one connector to the compressor. (just a single bullet type connector on top) I guess there is a fuse and relay, too, but I don't recall anyone saying that they found theirs to be faulty.

 

Thanks for the added info, I guessed the belt thing would be a PIA...that's why I'm cautious about doing the job myself. It's a pity because apart for that it should be quite an easy task to remove the compressor, should I really need to.

 

You really do need a second hand to drop an allen wrench to secure the tensioner. Otherwise, just get a good set on things, and remove your dipstick - I ended up breaking the handle on mine with the crowbar. <eyeroll>
The compressor is pretty easy - just two bolts (2nd is blind, though), just use the 'Rudy Method' - remove the lower engine mount, replace bolt, use ratchet strap to pull engine back, and you have enough room to work.
Also note that the OEM has two small steel pins that were rusted all to hell. The connectors just need to come straight out, but you don't have much leverage.

 

Ok, today I gave a try at the visual but I guess the fact the system is empty does hamper my chances to get decent results. Turning on the A/C the fan stays still, as for the compressor I couldn't understand if it had engaged or not. I guess I need someone to turn on and off the A/C while I keep looking at it, that way I'll be able to hear it engaging I guess.

I also gave a quick check at the electric wiring, the fuse is ok, the relay...well, if I checked the right one, which I'm pretty sure, there's something I don't understand but I'll check it again tomorrow with more time on hand; I should get an answer on wheter the clutch coil has failed or not from there, if I see an open circuit it has if not it hasn't.

Last, today coming back home I noticed that every time I switch the A/C on, the led on the switch stays fixed for some seconds, starts blinking for around half a minute, then it goes steady again. Does anyone know what that is about? I'll be searching info on the matter, but if you know it any suggestion is welcome :D

 

I've seen the AC blinky thing noted - likely to do with the lack of refrigerant.

The visual is pretty straight forward - the compressor is essentially an inset on the pulley. Use a flashlight and you can see if the inner section spins when the AC button is on. Again, lack of refrigerant may affect that.
You can check to see if the signal is being sent to the compressor, but it's kind of a beotch to get to that connector, as it sits on top of the compressor. I know others have done it though!

 

I'll try the flashlight thing today, as for the blink yes it should be connected with a lack of refrigerant, which ties well with the fact that the system is now empty

As for the signal being sent, what I've gathered is that if the line going from the relay to the compressor clutch shows as an open circuit then the clutch coil is gone, so I plan for the moment to check on this; the relay does get the 12v when the A/C is on so unless it's him which is shot, if the coil is ok the electrical wiring should be ok.

The other thing to check is the fan, I'll be checking its fuse today and try to understand why it wasn't moving yesterday, maybe I should have waited a little for it to come on, I don't think it was hot enough for it to immediately start; its lack of movement could still be connected to the lack of refrigerant anyway, so I guess to give more sense to these visuals I should probably buy a refill bottle for the system and fill it myself...should be cheaper than having a garage fill it just to make these tests and then find out I still need to reempty the circuit and swap the compressor...

 

Well, from info I gathered I can't check the fan until I fill the system again as it only comes on if there's at least 8 bar of pressure in the system...that's one thing I cannot check now then.

I tried seeing the compressor with the flashlight but being that I run a lowered MINI I can't get enough space to do so from under the car unless I remove the front bumper, which I didn't do today; I might in the next days tho.

I've just now got how I should check the resistance at the relay to understand if the clutch coil is gone or not, so no news on this side either...this thing of checking the system myself is getting lengthy, I just wish I had more free time to throw at it...

 

This is way to far along for a simple fix. Maybe, I didn't catch the prelims. Our A/C stopped cooling and we panicked. We gots to be refrigerated or we go bad. Any hoo, after the initial visual check w/ no glory, we had an epiphany. Have you checked your cabin air filter? If it's dirty, the A/C can't breathe. Cleaned it up, cool as a cucumber. A friend of ours has a Subaru. Took it to the shop for A/C problem, 800 bucks later - no glory. We explained about our experience and she's cool. Well, hot under the collar at her dealership.
Don't know if it helps. Just our experience w/ our A/C.
Peace,
Gary

 

Thanks for the input Gary, I'll be sure to check the filter!! Personally I've never checked it in 8 years of life of my MINI, I guess the dealership has checked it at service intervals but you never know with them...

 

If you haven't changed the filter, that can't hurt - they get pretty nasty. But I wouldn't bet on such an easy (and cheap) fix.
I checked the AC clutch from the top. You can't see it well, but you can definitely see it if it's spinning.
You're right on the low speed fan - need 8 bar (or 221deg) for it to kick on. You should be able to check it just sitting in a driveway. With no airflow it will kick in after not too long in summer. You can just barely hear low speed. High speed is unmistakeable.
Probably cost effective to use a self-administered dose of r134a, but if you haven't pulled a vacuum, the system won't be efficient, and it could cause problems (water freezing in the line.) How did you empty it? It should give you confirmation that your compressor is toast anyway (if it is.)
Note that you should change the drier if the system has been opened for any length of time.

 

The system has been emptied by the same guy I went to have it refilled; he tried the system but he got no cold air so when I went to pick the car uèp he told me I had to change the compressor. I don't know if he did any tests before coming to this conclusion tho, it was just a random guy I found handy to stop to on that occasion, as I thought it was an easy fix. Anyway he told me he could either leave the fluid in but then I'd have to pay the refill or he could pull the fluid away again emptying the system.

Anyway I'll check the filter and give another try at the flashlight from above and see where that leaves me...I can always go to another shop, have the system filled right in front of my eyes, run a couple tests there with a full system and see what happens.

As far as I know the system has never been opened unless it being empty counts as open.

 

I don't know if this is your case, but in my 2003 R53, I just had the same problem (AC not blowing cold air).

Found out that fuse F5 (5 amp) was blown. Replaced it and it blew again almost immediately. This fuse is for the power steering fan located under the car towards the front center. However this fuse is also necessary to have the AC engage properly (to be honest, I'm not 100% sure exactly why, but this ended up being the fix for me).

I jacked her up and followed these directions to remove and inspect the fan: http://www.billswebspace.com/MiniR53PSPFanDuctDIY.htm

Numerous threads abound on this issue and how this fan can easily get gummed up. Sure enough, the fan was filled with dust and muck and seized up hard, so when it was being engaged, it stuck hard, and the fuse blew right away.

I removed the fan from the bracket and liberally sprayed WD40 in it until I could get it to turn. After about 15 minutes of spraying, turning, spraying, turning, I was finally satisfied that it would move freely (as long as it wasn't completely busted). I reconnected the fan, put in a new 5A fuse in F5, and drove around with the AC on full blast. It took a few minutes, but I started getting nice cold air again, and the fuse didn't blow.

Did this repair just last night, so I'll have to see how it goes in the 100 degree weather we've been getting lately in Colorado, but so far so good.

 

Do test the resistance of the clutch coil on the A/C compressor to verify it is not the culprit. This is done by removing the A/C clutch relay in the engine fuse box. This post details it:

https://www.northamericanmotoring.co...40-post37.html

Quick and easy to test if you have a multimeter. The clutch coil seems to be a common fail point. Mine had a massive resistance, and it should be just a few ohms. Ordered the clutch coil and pulley from Rockauto and will be installing tomorrow...

 

Thanks Portmandia and gknorr for the imput; I'll be sure to check that fuse to see if it is blown and in that case I'll check the steering pump fan. As for the relay, I still haven't checked the compressor clutch resistance and the relay itself (you never know, it may have failed). Any suggestion on how to check if the relay is working? I as thinking about plugging it directly to a 12V source but I'm not 100% sure which pins I should connect to the 12V...

 

One quick and easy way to test it would be to switch it with the identical relay in the engine bay fuse box. I think it's the one for the fog light. It will be obvious once you take a look in there.

The relay has a diagram that shows how it's wired. You could connect positive 12V to the terminal for 87 and ground and see if you hear the A/C clutch engage and disengaging. Testing for the resistance in the same location would also work - it should be a small resistance.

 

This is the diagram on the relay:

 

Thanks very much for the info, I'll be doing these tests as soon as possible to get a better idea of what the problem is :D

 

OK, did the clutch coil resistance test as it was explained here:

https://www.northamericanmotoring.co...40-post37.html

and the result is that it shows 11 ohm or less with the car running, and less than 5 ohm with the engine switched off; I've measured it connecting to the ground of the battery and the socket for pin 87, here's a couple photos I took:







Is that right?

Also, I checked the relay itself as it is explained here:

http://www.bcae1.com/relays.htm

and it gives the right readings, plus the other relays in the engine bay fuse box give the same readings so either they are all blown or the A/C relay is working fine

I've tried checking that the relay gets the right voltage when the A/C is switched on and off from the cabin but I couldn't do it; I've read what is explained in that other thread, that I should check voltage between ground and pin 86 on the relay with the relay into the socket but I couldn't get to pin 86 with the relay in its position, it's too tight to insert the multimeter probe...gknorr, did you check that? How did you do it?

Besides that, I still need to check that 5V fuse of the steering pump...in the meantime I took out the cabin air filter...you don't want to know in which condition it was, , I guess I'll be giving it a good clean and put it back in the car.

 

Well, what can I say...I changed the cabin filter this morning, then I went to have the system refilled, and guess what? Ice cold again!! Either it was really the filter blocking the system (it was, after all, inclredibly dirty) or the first guy I went to refill the system was trying to scam me...

Still, thanks to all for the help and the suggestions!!