AC kept running non-stop 2001 E240

[RCA918]

Hi,

Can any 1 help me. My A/C kept running non-stop even if I have turn the engine off (key removed). I have unplug power cable to the fan unit beneath the passenger seat dash. Previously the A/C wont even function/response.

Kind Regards,

RCA918

 

[Apial]

This happened to my 300CE24 too. I fixed it by reconnecting the fan then I started to remove relays by trial and error from the drivers side of the engine bay behind the fuses. As luck would have it, I chose the correct one first time , and the fans stopped.

I opened up the relay and could see some burnt contacts that I cleaned up with emery paper. This fixed the problem but I chose to replace the relay in case it happened again.

 

[jberks]

The plug you removed is the 3 wire feed to the regulator. Check the current on the 3 pins. One will be live all the time at 12v, one -ve and the other is a switch feed that varies from 0 (off) to around 7v for full. If the switch feed is live when the power is off, you have a switching problem. However, the regulators are notorious and can switch themselves on when they aren't supposed to. So, if the switch voltage is 0 and the fan is still running, you need a new regulator.

 

[RCA918]

AC Problem

Hi,

How to resolve, if its a switching problem? How to remove the wooden cover for the centre console to get access to the AC Control Unit?

I dont seem to see any screws to remove the cover?

Thanks

 

[jberks]

Hi,
Its not too tricky, I believe there are screws in the ash tray, plus a couple of other steps, though to be honest I've not done it.

In any case, regulator failures are quite common (replaced the one in my W210 a couple of years ago) but I've yet to come across anyone with a switch problem, so my money is on the regulator. The regulator is a 15 min 'single spanner' job.

 

[DAVECLK]

RCA918
A continuously running fan on my CLK230 was diagnosed by JBERKS as the regulator, this was then confirmed by my local main dealer.
Out of interest a work colleague has had the regulator replaced twice on his SLK in the past 18 months or so and then this weekend its gone again!
DAVE CLK

 

[RCA918]

Does that mean the cause of the Regulator burning out is caused by some other parts?

Where is the Fuse for the AC be located? I have check the fuse in the boot, bonnet & inside the car & I dont seem to be able to locate the fuse?


RCA918

 

[RCA918]

Does that mean the cause of the Regulator burning out is caused by some other parts?

Where is the Fuse for the AC be located? I have check the fuse in the boot, bonnet & inside the car & I dont seem to be able to locate the fuse?


RCA918

 

[jberks]

Multiple burns outs are unusual. I was told that if the filters were clogged, the current draw on the fan could be excessive and this could damage the regulator but they do go on their own too. Its a solid state gizmo and from past experience, not a particularly good quality one.
The symtoms on mine were that it whistled exactly like a fan bearing. I asked my indy to quote to fix the fan and he told me about the regulator and that it was the most likely culprit (as always, he was right!). This went on for a few months, then the speed started to go up and down on its own. At that point I replaced it. Ran the car for another 2 years with no further problems.

Test the switch voltage as suggested above (centre pin if memory serves) and if as I suspect its 0v when its supposed to be off, pop down to your dealer and order a new regulator. They are around £125 from memory and a straight forward DIY job.

 

[RCA918]

I will check the voltage tommorow morning. Meanwhile I need to check where the Filter is, if it's block?

I'm a newbie but I have a meter to check the voltage, Can you help me how check the voltage? Which dials do I Turn to check the current on the 3 pins pls.


RCA918

 

[jberks]

set it to 12v (or 24v or whatever the closest is above 12), then I assume the cables on the plug in the footwell are red one one side, black on the other and something else in the middle. Put the -ve tester lead on the black and the +ve on the red. You should see a reading of 12v. Then put the red to the middle pin. With the heater fan switched on, you should see something between 2 and perhaps 7v (guessing). As the switch goes up, the voltage increases. The important thing is to check that when the switch is off, this drops to 0v. If you then connect the plug and the fan fires up, you know that the signal is telling it not to and the regulator is duff.

I assume yours is a normal circular knob hearter arrangement and not a digital climate system. If so, the filter is in the same place as the plug, just a bit closer to the centre console. There are 2 white slider clips. Slide them out of the way and drop the plastic cover they are holding up. Inside you'll see the filter. Just pull it out.

 

[RCA918]

Hi again,

Some 1 message me that for the Regulator, I can short test it by simply pushing some sepcific buttons on the AC but he cannot remember which buttons. Can any 1 please help?


Kind Regards,


RMT6668

 

[RCA918]

jberks,

I have already tested the 3 cable like you said. Negative Lead to Black and Positive Lead to Red (confirm 12V reading). Then the Red to the Middle Pin (also 12V reading), with switch 1. Changing the swicth to 1 to 5, still constant 12V reading.

Then thinking I may need the car engine turn on for this test. I turn on engine & see (with Red to Middle Pin). On switch 0, the reading became 15V but increasing the switch to 5 became 7V.

This is the reverse from what should be? At swicth 0, should also read 0V. Does this mean its not the Regulator?


RCA918

set it to 12v (or 24v or whatever the closest is above 12), then I assume the cables on the plug in the footwell are red one one side, black on the other and something else in the middle. Put the -ve tester lead on the black and the +ve on the red. You should see a reading of 12v. Then put the red to the middle pin. With the heater fan switched on, you should see something between 2 and perhaps 7v (guessing). As the switch goes up, the voltage increases. The important thing is to check that when the switch is off, this drops to 0v. If you then connect the plug and the fan fires up, you know that the signal is telling it not to and the regulator is duff.

I assume yours is a normal circular knob hearter arrangement and not a digital climate system. If so, the filter is in the same place as the plug, just a bit closer to the centre console. There are 2 white slider clips. Slide them out of the way and drop the plastic cover they are holding up. Inside you'll see the filter. Just pull it out.

 

[jberks]

The 7v at setting 5 sounds about right. The rest doesn't. Certainly, if the centre pin is live when you would expect the fan to be off (engine off or switch to 0) then there is a switching problem and your regulator is probably ok. I would expect roughly 0v at 0, 2v at 1, 3v at 2....7v at 5.

Try moving the switch through the settings a few times and see if the readings are consistent. Also 15v sounds a bit high given that the car shouldn't really be able to exceed 13-14v absolute maximum.

 

[RCA918]

Thanks,

If its a swicthing problem means I need ti change the swicth? Is the swicth what you term the AC control Unit? Is it easy to replace/access by removing the centre console?

Do I remove the cassete player 1st to access the screws to remove the wooded panel?

 

[jberks]

I'll step back at this point. I've never removed the console to the W210 so I'll leave that explanation to someone else.
Is it a digital controller?
If so, I believe there are some diagnostics you can run from the panel. If its the normal 2 knob and 2 thumbwheel arrangement, there is a bloke selling them on ebay at the moment.

 

[RCA918]

Mine a 2 dial & in middle is button for EC & Recirculation. No Climate Control.

Where abouts is the Ebay site selling this parts? Can you page me the www site pls?

 

[jberks]

The one I was thinking of was
http://cgi.ebay.co.uk/Mercedes-Benz...ryZ10398QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

He wants £100 but as I have no idea how much they are at the dealer or what some of the used parts dealers would charge I don't know whether thats a good deal or not.

That said, I paid £125 for my regulator so you're still getting away with less than I did!

 

[RCA918]

Jberks,

Some one just posted me that by switching the left & Right dial temperature, pressing the REST button and switching the ignition key at certain sequents or simulatenously and seeing the flashing of the LED REST will indicate the fault or even erasing the fault memory.

Are you aware of this preocedure? I've tried it but nothing? May be I press too quick or in wrong order?

Where is the relay & also the AC Fuse pls?

 

[jberks]

To be honest, no I'm not.
I think in your position, I'd pop it down to an indie for a second opinion before spending any real money. T am not aware that there are such things as fault codes on these. Sure the digital units do, but not the mechanical ones. Anything is possible though. The relays will be in the fuse boxes if they exists. Check the fuse book, it should indicate which fuse box.