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My family members 2003 ML350 is having an A/C issue. The compressor is turning on/off intermittently. I checked the evap sensors and other cabin temp sensors and they all appear normal ranges.
I have a compressor code, and here is the details when the compressor won't engage and the cabin temp begins to rise. When it runs, its pulling low 40's out of the vent. Pressures are normal and no leaks (I replaced a leaking expansion valve 6-months ago, evac and dye in...no signs of new leaks).
I'm not sure if the compressor is going bad, but parts cost of $500 with a new drier, I don't really want to "guess". Any suggestions on what else I could do to confirm its the compressor and not another electrical fault?
Compressor request % is 100% the entire time, so I "think" that means the system is asking for the A/C compressor to be on at all times, even when it decides to shut off for some unknown reason.
This image is when the compressor suddenly turns off mid-drive. Ambient was 95F so no reason at all it should turn off under normal operations. Have never had any issues until now.
perfect thank you! That is the direction I needed and I will get the car back over to me to inspect it. Cooling fans are unknown since the compressor won't engage while parked in the garage. They were working before all fine. The fans arent the reason why the compressor is not turning on either way I would imagine.
I assume if there is voltage at the connector, the compressor is the fault area likely?
You have stated that the compressor actuates on & off and with that if the fans are faulty, the compressor will be shut down. So you must monitor the fans while the compressor is working.
So I backprobed the connector coming out of the A/C compressor and got no voltage with the engine running and climate control set to the lowest setting. I didn't realize there was A/C data within the AAM module as well - so this module is showing the A/C compressor is OFF...but those engine and ambient temperatures don't make sense. Any of these give any indications that the issue could lay elsewhere?
Also the condenser fans turned on for a brief moment and then turned off, so they definitely work. I dont know if they turned on because the compressor briefly turned on then stayed off again, I don't know. Something weird is going on for sure. I'm trying not to "guess" and replace the compressor. I'd like to be sure its the compressor first. The fact the AAM module is saying the compressor is off, when it is off, makes me wonder if its not the compressor and something else. This module data looks whacky between the battery voltage, engine and ambient temperature and 40 BAR refrigerator pressure off??? none of these values make sense?
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