SL-Class (R230) 2003 -- 2012: Discussion on the SL500, SL550, SL600

SL/R230: 2003 SL500 F Relay and Fuse

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Old Aug 3, 2018 | 06:35 PM
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From: Peachree City, GA
2003 SL 500
2003 SL500 F Relay and Fuse

My climate vents do not operate at all, none. My SL does not have the relay not the 40A fuse above the relay. Is this the cause?
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Old Aug 3, 2018 | 09:36 PM
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Welcome to the forum! Please visit the User Control panel and complete your profile to add your location (at least country).

What fuse and relay are missing? I put together a set of fuse and relay diagrams for the R230 here:

http://benzbits.com/r230/Fuses/

There were many changes over the years, so refer to the proper ones for your MY2003.
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Old Aug 3, 2018 | 09:51 PM
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From: Peachree City, GA
2003 SL 500
The F relay and fuse just above are missing from my drivers side engine compartment. Not sure they should be there.

My issue is my climate control vents do not operate. I cannot control air flow at all. Driver vent is closed, middle vents are open and blowing, passenger vent appears to be partial open. Air also blows at feet always.

I read to check the fuses but have not figured out which fuse relates to vent controls. Any help is appreciated.

Roger
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Old Aug 4, 2018 | 09:33 AM
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Relay F is for the high pressure pump used for the "automated-manual" or "SMG" transmission (which I don't think was ever used in the R230?) so that will be empty on your car. Also, if the fuse is #12, directly about the F relay, then as shown in the fuse diagrams I posted, it is a "spare", so not used in your car.

If the ACC panel comes on and works at all, as in you can control the fan speed, then there is not a fuse or relay at fault. If the panel is totally dead, check fuse 23. Also check fuse 47 on the right side under-hood panel. Regardless, I doubt this is a fuse problem. I suspect your ACC panel is the problem. You should get codes pulled from it to see what it reports. Note that you can't do this with a generic OBDII scanner. You'll need to use a tool capable of reading MBZ's proprietary systems. Of course SDS (MBZ's Star Diagnosis, like the dealers use) will do it, but also there are the iCarsfot i980 and MBII units, and the Autel MD802 Maxdiag Elite.
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Old Aug 4, 2018 | 01:34 PM
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From: Peachree City, GA
2003 SL 500
The panel seems to work with exception of flow control. The open/close vent controls next to each vent does not work. Driver side vent is closed while others are open. Air flow is directed up and down and will not change regardless of panel settings.

Would the panel cause the individual vents from being able to open and close?

Roger
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Old Aug 6, 2018 | 01:11 PM
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I believe that the vent controls on the UCP are electrical, so if there is a failure of it (or an unplugged wire) that could be the issue. Do the other buttons (door locks, etc. ) on the UCP work properly?
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Old Aug 8, 2018 | 10:20 PM
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Yes. Other buttons like the central locks do work. Any control of air flow appears to be only issue. Individual vent open/close, up/down flow, I believe external/internal air intake. All panels appear to work as they light up and work unless it relates to air flow direction.

Roger
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Old Aug 9, 2018 | 09:26 PM
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I think you are going to need a proper diagnosis. The ACC system has codes that can be pulled with a specialized scan tool. If you want to DIY, then of course SDS (Star Diagnosis) will do this, but there are some other less expensive and less complex tools, like iCarsoft i980 (or MBII) and Autel MD802 Maxdiag Elite.
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Old Aug 14, 2018 | 10:18 PM
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I was able to get the diagnostics from my SL500. This error is repeated for all the M16/xx actuator motors. Below is just one example:

Communication fault between control module N22(AAC[KLA] control and operating unit) and M16/27(Diverter flap actuator motor)

Is this issue with N22 control module or something in between? Big job or little one?

Roger
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Old Aug 14, 2018 | 10:25 PM
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That would be my guess, or a wiring issue.
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