w124 Air conditioning fixed

[aka$h]

When I bought my 124 the air con wasnt working, as usual the seller said, it needs a re-gas.
Went to VCC (vehicle climate control) through Georges reccomendation, and it turned out to be a hole in the condenser, and one of the fans was also faulty, £330 later, its blowing ice cold air!
Apparently the fans fail which causes exceptionally high pressure within the system which is often the cause for leaks, so just check your fans come on when you run your a\c.

 

[fnkhan68]

are the fans suppose to be working all the time, as the fans on my car only come on when when the a/c is running and the car reaches a certain temp. also the compressor works intermittently. its a behr factory fitted system.

 

[aka$h]

within afew mins of switching your ac on the fans should come on.

 

[fnkhan68]

nah, doesnt happen on mine but still blows cold air, could be cos its running on r12 gas?

 

[MangoMan]

As far as I know the fans should run all the time the A/C is actually working, in other words compressing, compressor clutch engaged.

 

[david_h]

Akash can you post up the phone number/details for VCC

I need mine fixed, it's not fun stuck in London traffic boiling my brain just cause the aircon doesn't work.

thanks matey.

 

[bolide]

High pressure and low pressure

It was explained to me that there's a high pressure and low pressure sensor on the system. The former kills the compressor when the system is working and gets up to pressure - so it cycles on and off - and the latter detects a lack of gas (low pressure) and prevents the compressor kicking in. I think the sensors are on the pipework to the offside front of the engine bay in one unit with a 4-pin plug

I think the fans kick in as needed, driven by temperature sensors. They're controlled individually. They commonly fail, limiting the effectiveness of the cooling as the system will shut down earlier

Nick Froome
www.w124.co.uk

 

[Stratman]

The high and low pressure sensors are combined into one switch that's located on top of the receiver/drier.

 

[aka$h]

VCC:
020 8810 7666

Martin

 

[Will]

Also a very good idea to check between the fans and the condensor for any debris - what tends to happen is that dead flies/leaves and other muck gets caught in this spot, trapping moisture and causing the condensor to rot through and leak. I'd even be tempted to unbolt the fans periodically to get to the muck properly!

Better than a £200+ bill for a new condensor in a few years time too

Will

 

[fnkhan68]

today was a nice day, so i had the a/c on all the time. it was supherb, ice cold but the fans only came on intermittently. i actually asked a mechanic about this and he told me that the fans are temperature related so only comes on when needed and likewise with the compressor. this happens to regulate the temperature as mentioned by bolide in his previous post. thank god, with the weather warming up its a bad time for the a/c to malfunction!

 

[MarcusBenz]

Just thought I'd add my experience today with my w124 E320.

I discovered the air con wasn't working on a recent trip back to London (home) and thought I better get it sorted before I drive down to Barcelona!

So, got the local air con re-gas man out (John Kenealy - 087 2559706 for anyone based in Dublin) who did me a re-gas for €60 happy days. However, he did point out that my front two auxiliary fans weren't working and should be coming on to lower the air con pressure and keep me cool in traffic.

Went trawling through the internet to find out what it could be. I knew the fans worked because I've heard them come on full blast when the engine temp gets too high and they do a good job of cooling it off. Eventually found this gem on mbworld posted by a user called RPM:

You more than likely have a blown fuse on the relay for the low speed for the aux fans.Both fans run at the same time and are turned on by the pressure switch on the a.c. receiver/drier for low speed and by the temp switch on the water pump for high speed. Both speeds are controlled by seperate relays located in the back portion of the fuse box [towards the firewall]. It is necessary to remove the cover over the rear portion of the fuse box to access these relays.The cover is held on with six screws.You will find the relays have a fuse on top of the relay. If you pull the relays out one at a time you can check the fuses.

One replaced fused and a minute later and woosh, fans come on together! There's a blue relay with a 15amp fuse that burns out a lot apparently. So replaced it with a 20amp (apparently 25amp is recommended).

So I'm very chuffed now with that result! :bannana:

 

[Glenn Smith]

today was a nice day, so i had the a/c on all the time. it was supherb, ice cold but the fans only came on intermittently. i actually asked a mechanic about this and he told me that the fans are temperature related so only comes on when needed and likewise with the compressor. this happens to regulate the temperature as mentioned by bolide in his previous post. thank god, with the weather warming up its a bad time for the a/c to malfunction!

The fans are pressure controlled, all vehicles have slight differences to each other, some having 2 speed fans, some the fans come on as soon as a/c is switched on, a switch or pressure transducer in the high side monitors system pressure and operates the fans accordingly, the switch also doubles as a low pressure cut out for the compressor in the event of gas loss and a high pressure cut out in the case of condensor cooling problems ie fans or blockage, yes you should make sure the fans are working to avoid the compressor cuting in and out on the high pressure which can be 450psi compared to normal running pressure of 100-200psi.

 

[imadoofus]

I had my ACC regassed and tested a couple of months back.

Then on Monday this week, it wasn't blowing cold, so I took it back, and they found the high pressure switch (a red thing behind the NS headlamp) was faulty. This means the compressor doesn't kick in, and the system goes way over pressure - mine went to 20 (bar?) rather then the normal 3.

This blew a seal, which caused the system to leak.

In fact, the seal reseated itself. The swith was £47-odd.

PJ

 

[andy_k]

I'd even be tempted to unbolt the fans periodically to get to the muck properly!

not on a six pot W124 you wouldn't

Andy

 

[derin100]

I'm just resurrecting this thread because something similar to this has just SUDDENLY happened on my E320 Estate!

All seemed fine over the past couple of weeks that I've had it...until I started 'fiddling' with things!
It seemed to started after I connected a pressure gauge to the low pressure port of the A/C system...just as a check. There was only a tiny loss of pressure just as I connected up...nothing much. But I did noticed the gauge was reading high.
Anyway, immediately thereafter I noticed that "nothing" was working! No Auxillary fans turning on the front of the car, no A/C compressor kicking in and worst of all even the heater blower fan is not working on the dash!

1)I've checked and replaced fuse 7 in the fuse box having cleaned the terminals.

2)I've checked and replaced the 15 amp fuse on the blue relay in the box behind it having first pulled out the relay and cleaned its terminals before reseating it.

3) I tried to reduce the pressure by letting out gas via the low pressure port. This seemed to only let the pressure down very slowly and I can't help but think now all the refrigerant has gone!

I don't understand how this could have happened so suddenly if it were a pressure thing anyway?!

Any help gratefully received. Thanks in advance!

 

[jaymanek]

I think you need to have it regassed to the correct level and then see.

 

[derin100]

Yeah, I think you may be right. I think I'll have to get in touch with someone professional to look at it. Just a pain that it should happen now at the beginning of the weekend!

I just don't understand why I've also lost the heater blower function all at the same time.

 

[WG M-B]

As previously stated really
The fans regulate high pressure gas. The gas leaves the compressor at high pressure and high temperature. The fans kick in to cool the condenser /cool the gas down. This in turn lowers the head pressure of the compressor/ lowers the pressure of the gas.
Ac will still work without the condenser fans running but the high pressure side will blow a leak or the compressor will cook over time

 

[jaymanek]

Ahh sorry missed that bit, in this case you surely have a fuse or power issue somewhere.