[frustration_X_2]

I hate to beat a dead horse, or resurrect an old post, but...
I have a similar problem with a 1998 ML320.
Engine running.
Aux fans engage.
Interior blower running.
4.8V at the pressure sensor.
Static pressure on 134A system is 90PSI at 97F.

Alas, I've no voltage to compressor.

Anybody have another idea? ( Before I wire the compressor up to the fan relay! )

Not sure if it has any bearing, but the AC quit at the same time the water pump failed.
The AC quit before opening the hood to even look at the water pump, so it wasn't an ID10T induced failure. ( pronounced "eye-D-ten-T" )

 

[frustration_X_2]

UPDATE:
For curiosity's sake, I 'hot wired' the compressor to the fan relay. (Yeah, I know, but I did it anyway to test for functionality)

The compressor spins nicely. The pressures alter to just what I would think they should. (what they used to before this debacle.)

The problem is that it's still blowing hot air in the cabin!

No tick-tick-tick sound like the diverter motor is failing again, no fluctuation in temperature. Just nice hot air blowing from the vents regardless of the position of the HVAC controls.

How does THAT make sense?

The control module in the dashboard was replaced about a year ago. (with a junk one from Ebay) and it all looks ok.

I pulled it and opened the back panel to see if maybe it was fried... nope.
Put my ohmmeter on the soldier joints of the diverter controler... 3.7ohm in cool position, 1.0 in the heat position.

Any of your geniuses out there willing to help a dummy out of a hot zone?

 

[frustration_X_2]

Update number 2:

After "hot wiring" the compressor, I had the system evacuated, vacuum tested, and recharged with 27 oz of R134A.

removing the "hot wire" returns the same results... Aux fans run, Interior blower runs, compressor clutch does not engage.


Ideas? Suggestions? Theories? <sympathetic comments welcome so long as they are accompanied by cash.>

 

[frustration_X_2]

Let me start by saying how much I appreciate all of your assistance.
I live in Texas, and if it weren't for my wife's car, I'd have to take this one to the $tealer-ship to get some cooling by now.

That said...This will be this weeks 'fun-time'.

I will pull that pressure sensor again and make sure I've connected my leads correctly.
Can I 'jump' the pressure sensor plug to see if the compressor clutch engages or am I going to blow something if I do?
(Again, it's just a test, not a permanent fix.... but it would tell me if the sensor is bad.)

The AAC on a '98 ML is under the fuses, correct? So I've got a bunch of plugs to pull apart if it's NOT the sensor. :-(

I love the 320 drive train. (mine and my wife's are both 320).
But the 'chrysler' part of this bucket is driving me insane... the squeaks, rattles, broken parts and such are driving me insane.

Thanks again!