SL/R230: 07 sl55 no cold air from AC help
Thread Starter
Member
Joined: Jun 2023
Posts: 84
Likes: 5
98 SL500 sport
07 sl55 no cold air from AC help
so I just installed 5 piece idler pulley kit , vrp belt warp kit , vrp split cooling , 76mm SC pulley and tune . car drives beautifully but now I have no AC literately zero cold air which makes no sense considering it worked fine prior to the mods . no codes for AC on scanner and I can activate compressor with scanner but still no cold air. I did see on the data the diverter flap motor position is off some 1000 steps . can someone tell me 1 if splitting the coolant or the eco flash would cause this issue & 2 how I can fix the issue ?
Senior Member
Joined: Nov 2021
Posts: 471
Likes: 119
From: North West England
SL500
What scanner did you use. All are not equal! ODBII will not look for AC issues!
Will your scanner re calibrate the vents and flaps?
Do they all move when commanded by your diagnostic tool?
When you activate the AC, do you get the feedback that it is running at 100% (AC is variable displacement type, not one with a clutch!)
Does your diagnostic report back gas pressure? could you have damaged a pipe or condenser etc.
Will your scanner re calibrate the vents and flaps?
Do they all move when commanded by your diagnostic tool?
When you activate the AC, do you get the feedback that it is running at 100% (AC is variable displacement type, not one with a clutch!)
Does your diagnostic report back gas pressure? could you have damaged a pipe or condenser etc.
Thread Starter
Member
Joined: Jun 2023
Posts: 84
Likes: 5
98 SL500 sport
What scanner did you use. All are not equal! ODBII will not look for AC issues!
Will your scanner re calibrate the vents and flaps?
Do they all move when commanded by your diagnostic tool?
When you activate the AC, do you get the feedback that it is running at 100% (AC is variable displacement type, not one with a clutch!)
Does your diagnostic report back gas pressure? could you have damaged a pipe or condenser etc.
Will your scanner re calibrate the vents and flaps?
Do they all move when commanded by your diagnostic tool?
When you activate the AC, do you get the feedback that it is running at 100% (AC is variable displacement type, not one with a clutch!)
Does your diagnostic report back gas pressure? could you have damaged a pipe or condenser etc.
Wth scanner I can see I have 70% gas pressure
yes I can activate and get 100% from compressor
I did find I have a bad diverter actuator motor and I e also received the following codes mentioning the ac control unit is faulty . I had disconnected the cooling fan and believe that was the reason for the suction fan control code
Thread Starter
Member
Joined: Jun 2023
Posts: 84
Likes: 5
98 SL500 sport
The diverter motor is definitely not ok it shows the steps being -1000 and the AC control unit keeps clearing then reappearing coming back faulty . But the following codes pictured are constant
Thread Starter
Member
Joined: Jun 2023
Posts: 84
Likes: 5
98 SL500 sport
also when I was driving the car yesterday the red light for the battery lit up on the dash so I pulled over pressed the button to clear it and it didn’t come back . So I’m very much inclined to lean towards having an issue with the BCM
Senior Member
Joined: Nov 2021
Posts: 471
Likes: 119
From: North West England
SL500
You would really need to get it on STAR SDS diagnostics.
Not only does it give the codes and descriptions it gives guided diagnostics to narrow down the faulty component.
From what little I can see, have you checked out K57 relay (next to the BCM in the trunk)?
If I recall correctly this should be OFF most of the time, just turning on if the rear battery is a little low to enable the car to start.
Not only does it give the codes and descriptions it gives guided diagnostics to narrow down the faulty component.
From what little I can see, have you checked out K57 relay (next to the BCM in the trunk)?
If I recall correctly this should be OFF most of the time, just turning on if the rear battery is a little low to enable the car to start.
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Junior Member
Joined: Oct 2025
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Likes: 8
so I just installed 5 piece idler pulley kit , vrp belt warp kit , vrp split cooling , 76mm SC pulley and tune . car drives beautifully but now I have no AC literately zero cold air which makes no sense considering it worked fine prior to the mods . no codes for AC on scanner and I can activate compressor with scanner but still no cold air. I did see on the data the diverter flap motor position is off some 1000 steps, click here to learn more about potential causes. Can someone tell me 1 if splitting the coolant or the EcoFlash would cause this issue & 2 how I can fix the issue?
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