SL55/63/65/R230 AMG: Climate control nightmare
12-07-2020, 03:24 PM
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Climate control nightmare
Hello fellow Mercedes owners,
(Apologies if I bore you with this long paragraph and thank you for your help!)
I just recently purchased an SL55AMG from selling my E55 amg so I am familiar with the drivetrain but not the platform of the SL and was wondering if someone can shed some light on this issue in hopes for avoiding the stealership. So I purchased a 2003 SL55 AMG with around 62k miles and due to the mileage I wasnt really thinking that electrical components could fail at such low mileage I didnt bother to test out all the climate control functions as it was summer time and I was mostly worried about the Vario roof issue it was having but the A/C worked wonderfully. As the the weather started to get colder here in NE I went ahead and decided to disable the A/c And turn on the heat. I noticed that on the N22 Climate controller button where it says (A/C off) and its supposed to illuminate red dot to indicate that it has turned off the A/C was turned off was stuck on meaning I no matter how many times I pressed the button I could never turn off the A/C. Upon further investigation I checked all relays fuses looking at the fuse panel diagrams I was not able to pinpoint anything relating to Heating climate control. I then went ahead and saw online some people suggesting its the common heat control valve right in the cowl and changed that too with no luck. I did pull some paperwork and noticed that the rear SAM was replaced due to it being faulty by a Mercedes benz specialized shop chasing down Vario roof issues so I went ahead and inspected that SAM which seemed fine. Someone at some point was in the passengers side footwell testing voltages because two of the Can-Bus wires were slightly stripped and exposed. Regardless, I did not see any issues with the rear SAM as I ended up budging and bought a scan tool which gives me some functionality and data or errors. I ended up taking apart to inspect the from passanger underhood SAM to inspect the plugs and fuse panel which was corroded from water exposure so I ended up replacing that and that seemed to fix the AC button illumination and all the buttons seem to lite up fine and function normally. The issue that I am still having is that the signal is not being sent to the Heater control valve so it opens the door for coolant to flow into the heater core.
(Apologies if I bore you with this long paragraph and thank you for your help!)
I just recently purchased an SL55AMG from selling my E55 amg so I am familiar with the drivetrain but not the platform of the SL and was wondering if someone can shed some light on this issue in hopes for avoiding the stealership. So I purchased a 2003 SL55 AMG with around 62k miles and due to the mileage I wasnt really thinking that electrical components could fail at such low mileage I didnt bother to test out all the climate control functions as it was summer time and I was mostly worried about the Vario roof issue it was having but the A/C worked wonderfully. As the the weather started to get colder here in NE I went ahead and decided to disable the A/c And turn on the heat. I noticed that on the N22 Climate controller button where it says (A/C off) and its supposed to illuminate red dot to indicate that it has turned off the A/C was turned off was stuck on meaning I no matter how many times I pressed the button I could never turn off the A/C. Upon further investigation I checked all relays fuses looking at the fuse panel diagrams I was not able to pinpoint anything relating to Heating climate control. I then went ahead and saw online some people suggesting its the common heat control valve right in the cowl and changed that too with no luck. I did pull some paperwork and noticed that the rear SAM was replaced due to it being faulty by a Mercedes benz specialized shop chasing down Vario roof issues so I went ahead and inspected that SAM which seemed fine. Someone at some point was in the passengers side footwell testing voltages because two of the Can-Bus wires were slightly stripped and exposed. Regardless, I did not see any issues with the rear SAM as I ended up budging and bought a scan tool which gives me some functionality and data or errors. I ended up taking apart to inspect the from passanger underhood SAM to inspect the plugs and fuse panel which was corroded from water exposure so I ended up replacing that and that seemed to fix the AC button illumination and all the buttons seem to lite up fine and function normally. The issue that I am still having is that the signal is not being sent to the Heater control valve so it opens the door for coolant to flow into the heater core.
12-08-2020, 08:42 AM
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Okbarnett, I was wondering if someone went through the same issue on one and if its common so I can bypass trying to find some sort of wiring diagram which I do not have.
