Help with air conditioning

[David.X5]

Yes, That advice is very generic and would apply only to a system where the pressure is so low the low-pressure safety switch keeps the compressor from operating.

If the pressure you reported is the static pressure, you have most (say half or more) of a proper fill. There is no way to tell if it is completely full from the static reading.

[David.X5]

Just to be sure - are you aware the AC pulley turns all the time and the AC clutch engages the compressor drive only when it gets the right signal. The spinning pulley is not proof the AC is engaged.

[garfield81]

Originally Posted by David.X5

Just to be sure - are you aware the AC pulley turns all the time and the AC clutch engages the compressor drive only when it gets the right signal. The spinning pulley is not proof the AC is engaged.

Yes it's the inner disc/pulley that I was trying to see if it spinning and it looked like it was. I will try to move the car out of the garage to get more light and verify that again. Thanks for your help

[andrewwynn]

My X5 i bought 2 months ago had identical symptoms. It turned out to be a loose connector on the low-side pressure sensor. Follow the low side pipe toward the front of the car and there should be a connector about 15-18" forward of the low-side port.

I evacuated my system and started to re-charge and it wouldn't take more coolant because the compressor never kicked on. I was about to 'hotwire' the compressor to engage it when i bumped the connector to the low-side pressure sensor and it fell off.

The o-ring was WAAAY too tight; it took about 100# of force to get it to finally click on and then my compressor kicked on immediately, and I was able to charge the system. I couldn't see the inside part of the AC compressor clutch to even tell if it engaged, but if the pressure is higher than about 55# the compressor didn't engage.

I ended up buying a full manifold pressure kit (to help with the evacuation and also future diagnosis and recharge of mine and family/friends cars; my last coolant can cost me $6.70 at walmart of all places; identical brand that is usually $15 elsewhere). $7 recharge on an AC, i'll take it.

I had some bizarreness (wow surprised that didn't flag misspelled) with my electric fan kicking in 'all the time' when requesting AC before I finally got my AC actually working and now it only kicks in when it needs it. Not sure what that was about or the cause, but if you noticed your engine cooling fan running fast 'for no good reason', it may be a symptom.

Check that sensor connector; disconnect, check for bent pins, test for continuity (look up if supposed to be open or closed), and re-attach that sucker. I had my engine running with demand for AC set, and i heard the compressor click on the second i pushed the connector on tight enough.

Got my fingers crossed for ya. Though i think i read 30-35# is the recommended pressure for a refill, apparently measuring the exact weight of recharge from empty is the only precise way to do it and i will be redoing mine soon before august hits us.

I recharged mine to about 40# (can't recall ambient that day but the dial gauge on my refil kit had an ambient adjust and ranged 35-45, and i actually went up and down through that range until I got the coldest air coming out the vent).

[David.X5]

Just noticed you have an 06. Those will have the variable compressor and not the single speed unit like in my 01. Troubleshooting is a little different, but what we have all suggested remains true - those pressures suggest compressor isn't running for one reason or another v

[andrewwynn]

Originally Posted by garfield81

2.) I got the gauge as a separate part and the refrigerant can separate. And the gauge had instructions to check pressure before screwing in the can and only screw in the can if the pressure is low. So I did exactly that and as soon as I clicked in the gauge the needle jumps to 100 psi (As per chart it's supposed to be 35-45). I then unhooked the gauge and needle was stuck at 100. So I pressed the trigger without the can screwed in and noticed a puff of air/gas and the needle reset to 0. I tried it again and the needle again jumped to 100. So do I have a bad gauge?

That is normal operation. There is a one-way valve in there somewhere to make it that way, it confused me the same way when i started my version of your process. To add more confusion; since my compressor wouldn't run, my 'low side' ended up at 90PSI even though it was really 40 maybe.



Everything i read from your posts indicates compressor not running to me. When i was 'at your stage' My next step was to hotwire the compressor to make sure the clutch engages, but i by insane luck happened to knock off the sensor wire connector that was causing the system to not run.



-awr

[garfield81]

So I finally had a chance to check things around. Did a cold start and verified compressor clutch and it was stationary. Aux fan was also not running. Turned on Max AC and compressor clutch engaged and spinning. But no cold air and aux fan stationary. Verfied compressor clutch again by turning AC off and then back on.
Waited for about 2 or 3 minutes and still no cold air and aux fan stationary.
Closed hood and went for a drive. Shortly after driving there comes the cold air.
Back into the garage and noticed aux fan running.
Connected gauge and read a little over 35. Bmw dash showed outside temp of 68. Seemed about max so did not recharge.
Just as sanity check turned off AC and both compressor and aux fan stopped.
Turned AC back on and both compressor and aux fan running. Also AC is blowing cold air.

In short, on a cold start turning on AC while car is stationary there is no cold air and aux fan not running. As soon as I start driving AC starts blowing cold air and also Aux fan starts spinning.

[andrewwynn]

My first instinct is an issue with ambient temp sensor. If it thinks it's too cold it won't let the system run. A few other sensors similar. My low side pressure sensor was loose and if it jiggled closed from motion could give results above. It would be GREAT to find a proper diagnostic flow chart. I wasn't able to find one. Anybody aware of one?


Sent from my awrPhone using Tapatalk

[mbmw]

Hi,

the aux fan will only come on when the high side pressure increases to a certain pressure. so I wouldn't worry about that right now. Anyway while driving with sir entering the front of the car, this will simulate the fan running. This could also however be associated with the system not having enough refrigerant. I'm not a fan of diy kits as you can do a lot of damage if not sure of what you are doing. By the way I'm in the refrigeration and air con business so I do understand these systems well. Anyway your first course of action should be to physically check the suction pipe.It’s the bigger one returning to the compressor, usually has the charging up-stand connected to it on BMWs.Once the system is running this pipe should be sweating but not frozen.Also the discharge pipe (small pipe from compressor to condenser) should be too hot to touch and the liquid line from condenser to the fan coil, should be warm to touch.So if the suction is warm of the discharge not too hot to touch, then it is reasonable to assume that you need refrigerant.When adding do so very gradually and wait for pipe to be as I previously described.This is old school stuff but can, with experience, work as good as using a gauge (especially if broken).One other point is that if the system is not operated regularly, then the o-ring seals can dry out and cause gas to leak.FYI the oil circulates around through the system along with the refrigerant. Regarding your compressor, I would doubt very much that it is faulty.It will either be working or very badly damaged.I hope this helps you a little.

[David.X5]

sounds like the fan or an intermittent open wire. Always tough to troubleshoot...