Turbinator1990

Had the car for about 3 years now and been battling issues with my Aircon, shops have not been much help either. I have read multiple post on this forum and tried all the common fixes. I am hoping its not a bad Front SAM unit.


Below are my findings and what I have done so far:

1. Bought car when A/C not blowing cold; passenger side was blowing warmer, rear vents blowing hot, once in the while in the morning when turning on window defroster the vents would stop blowing
   1. Shop added Freon and dye to check for leaks
   2. No leaks reported ad both sides blow same temp but still not "full cold"
2. Replaced compressor, collapsed A/C line, Heater Changeover valve, outside ambient temp sensor (Shop)
   1. A/C blows a bit colder, once in a while it blows full cold (for like 5 minutes) even the rear vents.
3. Finally take the car to a friends shop just to check out the more detailed codes:
   1. AC - Air Conditioning 9450 B31 (C-ACC Multifunction Sensor)
      1. Sensor Replaced
   2. 9460 A32n1 (Blower Regulator)
      1. Rarely in the morning if I was to use defroster the blower fan would turn off for about 5 minutes.
   3. IC-Instrument cluster​​​​​​​ 912E ROM: Read Error
      1. ​​​​​​​Replaced the Aircon Cluster - Did not fix issue
   4. SAM_DR - Driver Signal Acquisition and Actuation module ​​​​​​9026 Component M16​​​​​​​/32 (Heat Exchanger Shutoff Motor) or lead has a short circuit,

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konigstiger

9026 valve, 9063 sensor

Turbinator1990

Both sensors have already been replaced by the shop I used to go to. I bought the parts myself, unless I have reason to believe the shop didnt install or incorrectly installed both sensors I do not think those will be the issue at this point.

I ordered my icarsoft MBII code reader for mercedes so hopefully I can pull up the codes again. Asking around some other mechanics they had told me to reset the A/C system and it should solve my issue.

Bankroll

Proper diagnosis is paramount. As a service professional, I don't get paid for unnecessary, and/or incorrect repairs. Being honest has it's downsides...LOL.

Mercedes indy shop, that is well versed in A/C, or the dealer. Need the proper scanner, and the skills to interpret real time data, no just read codes.

Turbinator1990

I think that is where I got screwed by the Mercedes Specialty shop whom I trusted for the other work they did to my car (Reputable E55 owners as well and known in the community). They assured me that it was my A/C Compressor that was giving issue, later did I find out it was not the cause of my issue and simply started with the most expensive fix they could do to my car. I complained to them multiple times that my A/C issue was not fixed, they can informed me that they would need to change out more parts to fix the issue, which I found to be not the case.

Lessons learned on my end is not to be completely trusting, get my own Mercedes specific code read SAM/CAN issue codes and not just check engine light codes, and find a reputable Mercedes shop.

Bankroll

Forget the cheap code readers.