AARG

I have not been able to fix my AC issue. I checked everything. and I mean everything. refrigerant, relays fuses all is in working order, I checked the connector that goes to the compressor and it gets 13.7 volts. puggled and unplugged. but the clutch does not engage.
I also found a procedure to reset the AC system and it did not work. I tried putting the key on the start and within 20 secs pressed the defrost and recirculation buttons and nothing happened no blinking no codes no restart. nothing. an help would be greatly appreciated.

Thank you.

Maj. Dundee

Could you tell us what year ML63?

Do you have a scanner that can read A/C Codes?

AARG

2009 and I dont have a scanner. but I think I found the flaw , it is some sort of solenoid that engages the clutch I belive it is called POA valve. it smells burned. I tested it with 12 volt current directly and it it was shorted.

do you think you could help me find the part # it had a c clip to remove. my vin 4JGBB77E09A475499

thank you in advance

Maj. Dundee

This POA valve you are referring to is called the Expansion Valve. M/B shows it in the diagram but does not show a part number in any W164 model. You will have to call Merc. to get the part number.

wannawagon

I know the compressor in the ML320CDI doesn't have a clutch. It seems to be a swash plate design that the compressor constantly spins but the amount of compression in the compressor is varied by the length of piston stroke.

The symptom was it got noisy for a while (mainly when driving - a fluctuating noise, I actually thought was a clutch in the transmission locking up etc) but it eventually stopped about 30,000km later

But if yours has a clutch maybe its a AMG thing

AARG

Actually it's the compressor control selenoid. It goes inside the compressor. It has 4 orings. Checked the groynds. Saw the other thread that you posted on how to test for ac module and it was in working order. Then tested the valve and bingo. I found a replacement. The are supposed to have good reviews. If it does not work I'll buy a new oem compressor.btw I read the codes and had code 9006.

AARG

not a clutch, it has an electric control valve. And it does not make any sound

wannawagon

I am a bit confused - you were the one that said it was a clutch controller. Beyond me

Good luck

AARG

I checked the following, ground to compressor ok
ground to control unit ok
Freon level ok
Solenoid control for ac compressor ok
checked all cables for continuity ok


Plugged the solenoid outside the compressor and still error code 9006

besides this I made the following tests, I unplugged the compressor from the harness and supplied 12 volts directly to the solenoid to force it to engage and nothing,
plugged the scanner and commanded the compressor to engage and nothing,
it always gives me error code 9006.
checked the front of the compressor since it uses some sort of mechanical failsafe that if its stuck it brakes and does not damage anything else and also in order.

on the bulletin from MB it says that error code 9006 its not caused by a bad compressor. that is why I am running all this tests.

any other ideas ???
thank you in advance.

Maj. Dundee

Here is the bulletin you mentioned, but how did you know where grounds W29/2 & W16/4 were?

The compressor is self-grounded by the bracket it get installed in. Did you remove the compressor and reinstall it?

Did you consider getting a new harness mentioned in Xentry Tips?

AARG

Found the bulletin online and checked. I have the 2 cable harness. I check for continuity and resistance. All good. I think it's the compressor itself. There is no other explanation. And I did not remove the compressor. Probably the failsafe that goes behind the pulley. Since I forced the selenoid by connecting 12 volts and it's not compressing

Roy mb

Do you fix it?

AARG

Yes new compressor. Old one was toast