E53 air con compressor not switching ON

[kanewesley]

I have a 2006 E53.

The air con is not blowing chilled air.

ths system seems more complicated than the one on the space shuttle.

I connected INPA andwhen I switch on the air con,.....I expexted to see the Air Conditioning Compressor switch on.

It Didn't

Whta criteria has to be met before this compressor switches on please?

[Alan Gunn]

Mine didn't work when I first got the car.
Went to ATS for a re-gas which they did but it still didn't work (so no charges).
Took it to a BMW indi I know who's a grumpy git at the best of times.
Told him what I wanted and he just mumbled have you tried the pressure switch in the pipe and walked away (proper grumpy).
With that information I bought a second hand one as didn't want to waist money but it fixed the problem.
On my e53 it is easy to change as it is looking at you just behind the drivers side headlight and just unscrewed but lost no gas as it is a valve type fitting.

[X5Sport]

E53s lose around 15% of the refrigerant year on year, more if the system is not used at least once every couple of weeks.

Low pressure will prevent the above mentioned switch from turning the system on in order to stop compressor damage.

You should hear a loud click from under the bonnet (compressor clutch activation) so if that doesn’t happen get the gas level checked, then the switch.  Your electric fan should also kick in.  If it has gone faulty than can also inhibit the systems’ operation.

[kanewesley]

Thanks Both of you for replies. Very helpfull

First job I think then is to get it regassed.

Is there anywhere, I can get a readup of how the system works?

[kanewesley]

3 more things if you don't mind.

i)  does the fan come on when you press the aircon switch or is that only operable if there is gas in the system?

ii)  can the pressure switch be momentarily frigged to prove the system works given the correct amount of gas pressure

iii)  Can the actual gas pressure readout be monitored / looked at using INPA?..What is the minimum pressure required for the system to work?..is that detailed anywhere?

[X5Sport]

[quote="kanewesley"]
3 more things if you don't mind.

i)  does the fan come on when you press the aircon switch or is that only operable if there is gas in the system?

ii)  can the pressure switch be momentarily frigged to prove the system works given the correct amount of gas pressure

iii)  Can the actual gas pressure readout be monitored / looked at using INPA?..What is the minimum pressure required for the system to work?..is that detailed anywhere?
[/quote]

i) from memory it only comes on if the pressure is OK.  A couple of folks have suffered fan failures recently which are a pain and almost always need replacement as they use PWM Control rather than just being 12V.  New ones are very expensive. 

ii) pass - but someone may know.  :-[  In theory if it just an on/off then yes you could just bridge the connection.

iii) I think it is just a pressure switch activation.  INPA should be able to tell you if the system has an issue though?

I got a regarding kit from Halfrauds which has a separate pressure gauge (you can buy gas and gauge separately) and connected the gauge to check the pressure before adding gas until it read correctly.  They have changed to a ‘pro’ gauge at silly money, but Amazon offer the STP equivalent...

gauge kit

[kanewesley]

PMW control?

INPA didnt show anything abnormal as far as i could tell apart from the fact that when i pressed the aircon switch, the compressor didnt start.

Under the bonnet, neither the compressor nor the aux fan  started.

There was some indication in INPA = dyn. press =30????

do you know of anywhere I can readup on how the system works please?

[X5Sport]

Pulse Width Modulation = a digital signal used to control variable speed fans such as the A/C uses.  The longer each ‘pulse’ remains on, the faster the fan.  Same system as used in most modern computers.

Never seen anything yet for the E53 and the links to the BMW Training notes from Xoutpost now only point at an expired domain.

Low side operating pressure should be between 30 - 40 psi with the engine running.  Low pressure is the most frequent reason for no system function and if the gas hasn’t been checked for a few years (or the climate A/C not used = snowflake symbol off) there is a high likelihood of that being the cause.  My E53 was checked every three years and I do the same with our E46.  I’ll be checking the X6 pressure this summer too, though it seems fine.

[kanewesley]

OK Bud.....think I'll start with a re gassing

[Alan Gunn]

A lot of places are the same as ats.
If no improvement after regassing then no charges.
Phone round for a price.

[kanewesley]

Right....Update......

aircon been regassed. (£55 at the till )

ice cubes now being spat into cabin from air vents. 

only thing now, the auxillary fan never starts 

[X5Sport]

Good news on that front, and keep monitoring that fan.  Mine always came on (at least I’m sure it did) even very slowly and I had multi-zone climate which might make a difference.  If the system is running then good 

If it is going down to 16°C and up to whatever the max is then it’s fine.  If the weather warms up again and you keep the climate on its lowest setting and you get a noise like an aircraft prop on full tilt from under the bonnet then all is 100% fine.

[kanewesley]

There are 2 zones in the front, driver and passenger, (if thats what you call multi zone), and maybe the rear seating area is a zone.

Why might that make a difference to the fan coming in?

And are you sayiny the fan may only come in when it,s very hot 'n sunny?

[kanewesley]

Excuse the bold

[X5Sport]

It sounds similar in the front, but having got rid of mine 7 years ago I’m having a brain fade on just what I had controls wise in the back.  I think each passenger could set their own temp (as they can in my X6] rather than a one setting only option.

If it works across the full range then it’s fine and maybe that unless the outside air temp is a lot higher, extra cooling isn’t needed.  BMW make so many little changes each year, not all of which are obvious, that I might be sending you down a rabbit hole!