Air con - problem

[DrNick]

My aircon appears to have stopped working. It was OK a couple of days ago, but to be fair has always seemed a bit weak. I don't get a light on the EC button, which I think is supposed to light up if the gas pressure is too low. I believe the compressor is kicking in but I would like to know if there is a quick test to check this before I get an AC man in. I suspect the gas is too low to be useful but want to check obvious things first!

Its a dual zone normal air-con (rotating temperature control knobs) on a W210.

Anyone have any insights?

 

[Stratman]

If you mean you want to test if the compressor is kicking in then just look under the bonnet.

With the engine running and you looking under the bonnet have someone turn on the A/C. You should hear a clunk and the center of the clutch should start rotating.

I don't know if it applies to your W210 but my W202 has the same controls as you describe but on mine the red light in the EC switch is on to indicate "Economy Mode", ie A/C switched OFF.

Red light ON A/C OFF
Red light OFF A/C ON

Reagrding pressure, most independent A/C shops will check it for you on the spot if they're not busy. Many won't even charge for it.

 

[SimonsMerc]

See the instructions here:

http://www.mbclub.co.uk/forums/showthread.php?t=14961

-simon

 

[Dave Bailey]

My aircon appears to have stopped working. It was OK a couple of days ago, but to be fair has always seemed a bit weak. I don't get a light on the EC button, which I think is supposed to light up if the gas pressure is too low. I believe the compressor is kicking in but I would like to know if there is a quick test to check this before I get an AC man in. I suspect the gas is too low to be useful but want to check obvious things first!

Its a dual zone normal air-con (rotating temperature control knobs) on a W210.

Anyone have any insights?

Mine appeared to give up the ghost a little while back. It turned out that the cabin filter was seriously clogged. Replacing it solved the problem.

 

[DrNick]

Thanks for that. I changed the pollen filter a while ago, but its probably worth a look. The compressor is spinning when I press the EC button, and stopping when I push it again, so that looks OK. I'll get the gas charge measured next if the filter looks OK.

 

[Stratman]

The fact that the compressor engages would indicate that there is at least some pressure in the system. on top of the drier/receiver is a high/low pressure cutout. Basically this will stop the compressor running if there is too little or too much gas pressure.

I'm guessing that your problem is that the air coming from the outlets isn't cold enough. Really silly question, grandmother and egg-sucking time but what temperature have you set on the red/white/blue thumbwheels? The outlet air is a mixture of air that has passed through the evaporator (cooled) and air that has passed through the heater (heated). Turning on the A/C doesn't 'bypass' this mixing process, it just mixes cooled rather than ambient temperature air with the heated stuff.

 

[DrNick]

I've had the dials in all the positions! I think it is still working a bit ie can cool the air by a couple of degrees. I've got it booked in for testing next week. I think it just needs a refill/top up

 

[DrNick]

Update. After a few days it started working again, but I took it into the AC man (Reader Air Con in Woking - I can recommend) and he gave it a quick look over (including the pollen filter) and then drained the gas and refilled. Apparently it only had about half a charge in it. Since being refilled it gets pretty cold in the car now, so it was worth having it refilled. Lets hope the not working problem was related to this - not convinced at present but I'll only be sure when it does it again. Lets hope I'm never sure then!