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My American ac skills are not putting a dent in this Mercedes. I can pull a vacuum and it will hold with no problems but I can't get it to take a charge. I tried some of the AC controller, reset two button, push tricks, etc. Learned there is no relay that I can jump out. I was going to check for a fuse but I don't have a little fuse chart. I'll have to find that online. I also have some stepper motors that won't calibrate. This is going to take some work. Feel free to chime in!
AC issues are always going to be a headache. There are instances where our Front SAM has certain components that fry and leave the AC compressor inoperable since it doesnt receive any power. These cars are so finicky when it comes to electronics. I took my car to the dealership and they told me I needed a new AC Compressor and that my battery was also 7 years old and needed to be replaced. I got the battery replaced first to see if any changes occurred. Funny enough it solved my AC issue. Im not sure what was wrong but my hypothesis is that the compressor was not receiving enough voltage or something, I honestly dont know. What I do know is that the dealership tried to make a quick band off of me by suggesting a new compressor instead of looking at the system.
It sound like whatever you are dealing with is an electrical problem. If what I say is true then check all electronics in the AC Module and Front SAM are working/getting sufficient power. I never expected my old battery to be the fix, but here we are.
Long story short, find a shop you trust. I mean a shop you can seriously stand behind (as if the technicians were personal friends/family). AC repairs can be costly and it makes no sense to fix what isnt broken. If you can build up a relationship with a good AC shop, that would be even better.
AC issues are always going to be a headache.........If you can build up a relationship with a good AC shop, that would be even better.
When I was researching I think I read some posts about your travails. I will try to find a good shop and somebody to trust, but in the meantime I'll keep poking around. I'm pretty good with cars and electronics. I'm an industrial electrician by trade so I can find my way around pretty well. But, this is a very different automobile so I've got a lot to learn. Thanks for the encouragement! I really like this car and I think I want to make it run right. Your suggestions about a battery are good. The battery that's in this car isn't correct. I don't think. It's also not fastened down, so I may just look at getting the correct battery and hold down hardware. Not necessarily Mercedes branded battery, but the correct size and amperage ratings.
If my advice is worth anything. Get the OEM Mercedes brand battery. Trust me. My previous one was an interstate battery that was the wrong size (and who knows what else was wrong with it). I was hesitant at first because I thought I was going to have pay an absurd amount, but the battery came out to be $219.00 at my local dealership in Durham, NC. This was the same price as the other high end batteries I found from auto part stores (and lesser quality as well from reviews I have read). When it comes to seniors and electronics, I stick with BOSCH/Mercedes brand. I tried the other stuff and it wasted my time.
Thanks so much for your candor. That is reasonable price for a battery so I will probably do the same thing. I'll let you know how it goes in this thread.
I have to drive the car more, in order to pass emissions. Once I get that done, I will change the battery to the correct unit. In the meantime, I am reading up on how the system works. The car is not with me right now, so I cannot check to see if I have a magnetic clutch for sure, but I believe that I do. I also believe that I have 4 sensors, potentially: outdoor temperature, indoor temperature, coolant pressure and possibly a rain sensor. Anyway, lots to learn.
I worked on the car some this weekend. The driveline needed to be refreshed. While I was working on it, I identified the outdoor temp sensor and it seems to be functioning correctly. Not sure how to verify the other inputs.
05-19-2023, 01:51 PM
