A/C Kept running non-stop-2001 E240

[RMT6668]

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,

RMT6668

[RMT6668]

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,

[blindside.AMG]

I'd like to help but I don't really understand what you're looking for. Could you please clarify??

If I understand you correctly your blower motor is staying on with the key out of the ignition?? You're on the right track if you think it's the blower motor regulator....but it could also be the A/C pushbutton unit. If I can remember tomorrow at work I'll look up how you can check the codes from the pushbutton unit.

[RMT6668]

Thanks.

I realise mine dont have climate control/ The push buttons are only EC & Recirculation . However there are 2 dials, one is 1-5 Fan Blower Speed & 2nd dial is to adjust the Fan Blower Direction to the leg, front, top etc.

Hence there is not much push buttons.

[blindside.AMG]

Originally Posted by RMT6668

Thanks.

I realise mine dont have climate control/ The push buttons are only EC & Recirculation . However there are 2 dials, one is 1-5 Fan Blower Speed & 2nd dial is to adjust the Fan Blower Direction to the leg, front, top etc.

Hence there is not much push buttons.

Oh, I wasn't even aware you could get codes out of the older style A/C modules like that. I forget to check today at work but I'll remember tomorrow.

[RMT6668]

OK Thanks.

Whilst you are at work please copy me the E240 W210 AC MANUALS, DIAGRAMS, SCHEMATICS etc. If you have soft copies of that, pls email me all. Thanks again.

[RMT6668]

Blindside,

Do you the method to test the 3 pin cable connecting to the REgulator, using a Multimeter. Its meant to have positive & negative 12 Volts & if its constant on 12 V means the AC Control unit at fault instead of the Regulator. Can you access this info from work pls.

[RMT6668]

Is it possible that the Relay Power Contacts are welded & Sticking? Its a 1 inch Box Plug in Cube, 5 pin relay on the engine L side?

[RMT6668]

If its a faulty control unit & I bought the car new in Aug'2001, do you think it will still be under warranty?

I will be ashame for Merc to have such a bad quality. If its warranted I will not take the part apart

[RMT6668]

I have remove Fuse no. 4 & 7 for the Air Conditioner but the AC Blower continue blasting away. Does this conclude its the AC Control Unit Faulty & not the Regulator ?

[RMT6668]

Where is the thermo sensor switch?

[blindside.AMG]

Hey, sorry to leave you hanging for those couple days....St. Patty's day weekend here ya know.

Unfortunately I wasn't aware you were in Australia so I'm not sure how much I can help you as far as wiring is concerned since we don't have the E240 over here in the US. I doubt the wiring is too different but I can't gurantee anything. Also, I am unable to save wiring diagrams and schematics so I can not e-mail them to you.

From the wiring diagram I have here it states the following about the 3-pin connector at the blower motor regulator:

Pin 1 - 4mm Brown wire is the ground wire
Pin 2 - 4mm Red wire Main Power, 12 volts at all times
Pin 3 - 0.5mm White/Pink wire, Blower control voltage; with ignition ON you should have around 0.7 volts with blower on lowest speed, around 5.0 volts with blower set on "max"

It is very odd that you removed fuse 4 and the blower keeps blowing since that's the main voltage supply to the blower motor. To be honest, at this point, since I work at a dealership I would get a new regulator from the parts department and test fit it to see if it works but I don't think you have that option. I think it may be worth it to save some time and just take it to a shop and have it looked at. And it does sound like your warranty has expired. Mercedes come with a 4 year/50,000 mile warranty here in the US (not sure about Aus).

[RMT6668]

Hi again,

The VIN # WDB 2100622B369454

I finally manage to pull the AC Control Unit off. Attached are the pics I have taken. Surprisingly with the AC Control Unit disconnected, the Blower still kept blasting away. Is it back to the Regulator or even the Thermo Sensor Switch Faulty?

Can some one pls lead me in the right direction very much appreciated.






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[RMT6668]

Hi,
I finally put the AC Control Unit back in the dash. I have tested the 3 pin wires using a Multimeter.
(1) Test the middle pin with AC switch disconnected--->0 Volts & plugging the 3 pin wire to the Blower turn ON full blast
(2) Test the middle pin with AC Switch connected ----->12 Volts & plugging the 3 pin wire to the Blower turn ON full blast
(3) Test the middle pin with AC switch connected (a) Switch 1---> 11 Volts (b) Switch 2--->10 Volts (c) Switch 3--->9 Volts (d) Switch 4--->8 Volts (e) Switch 5--->5.5 Volts
(4) With Engine On, test the middle pin with AC switch connected (a) Switch 1---> 12.5 Volts (b) Switch 2--->12 Volts (c) Switch 3--->11 Volts (d) Switch 4--->10 Volts (e) Switch 5--->7 Volts
Whats odd is that the Blower keep blasting away with or without the AC Switch connected or disconnected.
But the Multimeter detected 12 Volts in the middle pin when the AC Swicth is connected but 0 Volts when discoonected?