Aircon dead...

[lesage]

All of a sudden, when I try to put the aircon on, I get absolutely no response. The only thing recently done to the car was some welding which involved disconnecting the battery

Neither the normal nor the recirc switches work (ie neither the small yellow tell tale on the switch lights up, nor is there any reaction by the system, electrically or mechanically). Fuses in under bonnet (hood) box all seem fine & car's otherwise been ok. Was working fne during the summer.

Can anyone suggest where to start please? I did have an incident years ago when I changed the microfilter and didn't reconnect the wiring with excessive brilliance. However at that time the rear screen demist switch failed too. It's still working at present; just the 2 aircon switches are dead


1992 525iXaT 166k miles GD79080

[Tiger]

Check the refrigerant pressure level. If it is too low, AC will not work.

[BennyM]

I don't know what the weather is like over in the UK, but mine often won't light up if the outside temp is below a certain degree. Then when the weather gets nicer, suddenly the AC will come on without my telling it to.

[Paul in NZ]

have you checked under the rear seat for fuses related to a/c??

[lesage]

Check the refrigerant pressure level. If it is too low, AC will not work.
The weather was in fact bloody cold here (UK, south east)- not much above zero. I switched the aircon on in order to dehumidify...thats how I came to realise its wasnt working...

Im due to make my 800m journey due south to SW France o9n Sunday...praps the temperature will be tested en route, although its been cold there too, about the same as here...

[lesage]

can one check refrigerant pressure at home or is that a garage/stealer exercise?

[lesage]

[sorry--posted this first in wrong slot above...]
The weather was in fact bloody cold here (UK, south east)- not much above zero. I switched the aircon on in order to dehumidify...thats how I came to realise its wasnt working...

Im due to make my 800m journey due south to SW France on Sunday...praps the temperature will be tested en route, although its been cold there too, about the same as here...

[lesage]

No...will check this evening...

[Tiger]

I don't know what you guys can get in UK... First... does your car have R134A refrigerant or R12? If R134a, you can check yourself if your auto parts supply R134a refrigerant with a hose and gauge on it.

If you have R12, you need to buy an adapter... However, I don't know what you guys can buy in UK at auto parts store.

[lesage]

A green bmw label on the panel on which bonnet is mounted indicates R134a.

Is there a BMW kit available for recharging or is an independent OK, assuming one with gauge & hose can be found? Or is a kit recharge on a system which is as dead as mine not the recommended course for the novice?

[Tiger]

R134a is R134a... not car specific... Go to your local auto parts store and see if they have a R134a can with gauge and hose built in. In USA, you can buy this anywhere.

[repenttokyo]

the air conditioner will not turn on below a certain temperature - 15 degrees C i believe. It's in the manual, have a look.

[whiskychaser]

Kwikfit charge about £50 to pressure test and refill the system. But I think its a bit suss that both the aircon and recirc have gone west at the same time. As Paul said, best check the fuses under the back seat. While you are under there, check the climate control module - it controls the heated rear screen, recirc and aircon. Maybe it got nudged when the battery was being disconnected?

[Bill R.]

down when it reads 2 degrees C at the evaporator... If its as cold as i think it is your system won't work until it warms up. The 3 way pressure switch also will cut the system off if the low pressure side it too low. Temperature and pressure have an equal relationship with r134 so i wouldn't get too excited , I'd just wait until it warms up some and see if it works then.

[lesage]

Thanks Bill R and whiskeychaser.

Its pretty cool still here in London, maybe 3-5 degrees daytime; and at or near freezing at night; so between the cold and possibly low pressure in the refrigerant I have a decent choice.

Whiskeychaser mentioned the climate control module under the rear seat. Could he/ someone tell me how to identify this please..colour/shape etc etc?

[whiskychaser]

Thanks Bill R and whiskeychaser.

Its pretty cool still here in London, maybe 3-5 degrees daytime; and at or near freezing at night; so between the cold and possibly low pressure in the refrigerant I have a decent choice.

Whiskeychaser mentioned the climate control module under the rear seat. Could he/ someone tell me how to identify this please..colour/shape etc etc?

Hi Dave. Near Manchester and mine still kicks in at +3C. My memory is playing tricks - the climate control module lives under the dash behind the aircon evaporator. You know anybody closer who could run a diagnostic for you?

[sal_park]

Hi,

I'm pretty sure this will be an electrical issue (at least anyway). I'm in london too and my aircon light is on/has been all the time through this cold weather. Also if the aircon system is low on gas such that the compressor won't kick in and the aircon won't work, the green light on the switch will STILL illuminate. This is why I think you've got an electrical problem.

First step, as suggested by others is to check all the fuses. Have a look in the engine bay and under the back seat. All fuses will be labeled.

hth

sal

(Just North of London for the record :) )

[sal_park]

The only thing recently done to the car was some welding

Isn't this a classic way to kill the electronic on a car ? (assuming electric arc welding)

[lesage]

I dont know anyone who can run a diagnostic except one of the independents I use which ultimately I may have to do

Am persuaded by your comment about the system still kicking in at 3C, and similar comment from sal park, that this is an electrical rather than temp related issue. Will look under seat on saturday...

[lesage]

You & whiskeychaser have persuaded me re it being electrical (& pressure?), not temp

I think the system was last recharged by PO just before I purchased it in 2002, so I guess over that period things can lose pressure. I havent touched the AC since I've had it as it's been fine so far. What periods between recharges are typical?




Will look under seat on saturday...

[lesage]

Isn't this a classic way to kill the electronic on a car ? (assuming electric arc welding)
yes I gather arc welding is a classic way to cook electrics; however that was why the guy who did it disconnected the battery -- he was an classic (MG) specialist person (ie careful, sane :-) )

[whiskychaser]

You & whiskeychaser have persuaded me re it being electrical (& pressure?), not temp

I think the system was last recharged by PO just before I purchased it in 2002, so I guess over that period things can lose pressure. I havent touched the AC since I've had it as it's been fine so far. What periods between recharges are typical?




Will look under seat on saturday...

Even if the a/c is low on pressure this doesnt account for the recirc not working. This is a list of fuses from Bentleys. Some of them control other items like the horn, so if that item works you dont even need to check it:
Fuse 9 Horn, Climate control, aux fan
Fuse 19 Climate control
Fuse 20 Instrument cluster/check control, interior lights, side lights, climate control
Fuse 27 Climate control
Fuse 29 Climate control, inst. cluster, aux fan
Fuse 46 Climate control

[lesage]

Even if the a/c is low on pressure this doesnt account for the recirc not working. This is a list of fuses from Bentleys. Some of them control other items like the horn, so if that item works you dont even need to check it:
Fuse 9 Horn, Climate control, aux fan
Fuse 19 Climate control
Fuse 20 Instrument cluster/check control, interior lights, side lights, climate control
Fuse 27 Climate control
Fuse 29 Climate control, inst. cluster, aux fan
Fuse 46 Climate control
Whiskeychaser:
Thanks for that. I suspect the fuses you list are in the box under bonnet. Correct? I have AC rather than climate control but recognise the climate fuse no. refs you quote, which +/- coincide, & have tested each AC fuse in box under bonnet for integrity. Have now also looked under rear seat and cannot see any burnt fuses (nor any refs to AC either)

There will I guess be relays associated with the AC...do you know which ones are involved?

As the recirc switch also causes AC to operate (In mine at least) I'm not surprised that both are dead while rear demist is still working

I think that the fault is probably due to low pressure, rather than low ambiant temperature or electrical, just at present, so I'll try get it tested (FWIW, my manual quotes 1 degree C as the cut off temp for the AC system. Ambiant temp where I am now (SW France) is higher than this.)

[whiskychaser]

Whiskeychaser:
Thanks for that. I suspect the fuses you list are in the box under bonnet. Correct? I have AC rather than climate control but recognise the climate fuse no. refs you quote, which +/- coincide, & have tested each AC fuse in box under bonnet for integrity. Have now also looked under rear seat and cannot see any burnt fuses (nor any refs to AC either)

There will I guess be relays associated with the AC...do you know which ones are involved?

As the recirc switch also causes AC to operate (In mine at least) I'm not surprised that both are dead while rear demist is still working

I think that the fault is probably due to low pressure, rather than low ambiant temperature or electrical, just at present, so I'll try get it tested (FWIW, my manual quotes 1 degree C as the cut off temp for the AC system. Ambiant temp where I am now (SW France) is higher than this.)

Hi David, I'm not sure where all the fuses are. Inside the lid of the fusebox on mine there is a list of the fuses that are in there. 'Climate control' is just what the book calls it - you might see it called IKHR too :-) I take that to mean anything to do with the heating/ventilation/aircon. You can run the recirc on mine without the a/c. I think thats logical as if you are trying to warm the inside of the car you dont need the a/c on. But I'm sure someone will tell us which is normal. Hope the pressure check sorts it!

[lesage]

Hi Whiskeychaser

I have read on this board in the past that recirc also starts the aircon which it definitely did on mine; I agree it not evident as the French say. However, the Germans being clever, they presumably reckon that because your windows steam up if you leave recirc on for a while (I presume due to moisture on the occupants breath accumulating in the cabin), then aircon will dehumidify and stop or reduce the phenomenon

However they seems to have gone back to basics again with your car :-)

Yes,I too followed my front fuse box lid to identify aircon fuses & they checked out fine

[whiskychaser]

Hi Whiskeychaser

I have read on this board in the past that recirc also starts the aircon which it definitely did on mine; I agree it not evident as the French say. However, the Germans being clever, they presumably reckon that because your windows steam up if you leave recirc on for a while (I presume due to moisture on the occupants breath accumulating in the cabin), then aircon will dehumidify and stop or reduce the phenomenon

However they seems to have gone back to basics again with your car :-)

Yes,I too followed my front fuse box lid to identify aircon fuses & they checked out fine

Well my car is a bit of an oddball:D If you are trying to hunt down electrics check this link out. I think we have Shogun to thank for posting it:
http://www.armchair.mb.ca/~dave/BMW/e34/

[lesage]

To all my readers

The reason the aircon went dead was simply lack of pressure. Recharged. Sorted. It hadn't been recharged for at least 7 years, possibly more