W204 Electrical woes - Is my front SAM bad?

[AffectedArc07]

(first post here so please tell me if I am missing anything, apologies!)

Hello!

I have a W204 Facelift C200 CDI, everything drive related is absolutely fine, the car will drive with no issues, but the ancillary electrical bits are being a bit iffy, specifically:

• The indicator LEDs for the parking sensors button and eco mode button do not illuminate, but the buttons still toggle their respective functions (IE: Parking sensors doesn't have the little red LED lit up when the sensors are enabled, the radars on the dash still light up though)
• The cabin lighting and reading lamps do not activate when the doors are opened, but can be manually toggled using Xentry.
  • It is worth noting that if I unlock the vehicle at night, I can see the cabin lights flash on for a split second before going off.
• The backlighting on all interior buttons is non functional (none of the buttons light up in the dark, apart from the headlight switch, which is ironic given the next things).
• Whenever I start the car I see "Auto lights inoperative" on the drivers display, and the headlights are on at all times regardless of what the switch is set to
• The air conditioning compressor does not enable with the AC button on the climate controls, but can be manually toggled using Xentry (air blows ice cold and the values are changing).
• The value reading within Xentry for "Duct 1 of component S1 (Exterior lighting switch)" always reads "Left parking light" no matter what the switch is set to.
• The value reading for "Duct 2 of component S1 (Exterior lighting switch)" always reads "Value INVALID" no matter what the switch is set to.
• Auto stop/start does not work (ECO shows up on the drivers display in yellow, but then disappears after about 30 seconds of driving, pressing the eco button does not make this come back)
• Xentry shows circuit 30 on the front SAM has 0v, yet 30g has a nominal voltage, which I believe is switched from circuit 30 but do correct me if I am wrong.

Do any of these issues sound familiar to things dealt with, and if so does this sound like I need a front SAM replacement? The fact that everything that doesn't work can be manually enabled and disabled within Xentry makes me think its just a SAM software issue and not an actual hardware issue, but there is every chance I can be wrong here.

Car has about 101k miles, and I have replaced the auxiliary battery in the boot in case that was causing any of these issues, however that doesn't appear to be the case as the problems still exist even after a code clear.

Thanks!

 

[AffectedArc07]

Update - Garage has done several diagnostics and we can confirm the SAM is infact screwed. Ah well.

 

[AffectedArc07]

Got the SAM replaced, everything works now (bar the front courtesy lights), but if thats the only problem ill gladly take it over more weeks of diagnostics and the like.

 

[sonic]

Glad you found the fault Sams are always a good place to start, water in them is a big issue.
Front courtesy lights fault should be easy to fine.