MJJ
Active Member
- Joined
- Jan 13, 2020
- Messages
- 135
- Location
- Wiltshire
- Car
- '09 S211 E220 CDi manual - 197k miles and counting
Hi all,
I am struggling to solve a minor, but annoying problem I am having with my '09 S211, and wondering if anyone else has solved this. Googling shows a few instances of this being a problem for others, but no shared solutions.
So, the rear seat interior ambient, and main 'door open' lighting only works maybe 1% of the time. Reading lights work fine. No combination of rear dimmer button, or front overhead console button presses springs it to life, but occasionally, it comes on of its own volition and stays working for a few minutes. All other interior lighting is working perfectly.
Given the lighting occasionally works, I am ruling out bulbs and wiring. Investigating wiring diagrams in WIS show the lighting is controlled by two modules, 'Overhead Control Panel Control Unit' and 'Rear Signal Acquisition and Accumulation', i.e. the rear SAM.
I have scanned the car for faults with iCarSoft, and the only persistent fault is on the rear SAM module - P9078 Communication with the component H3 (alarm signal horn) is interrupted. iCarSoft shows an 'Upper Control Panel' which may be the same as the Overhead Control Panel in WIS, that has no errors.
My gut feel is a faulty/failing rear SAM, but if anyone has managed to solve this previously, please do share how.
Thank you,
Martin.
I am struggling to solve a minor, but annoying problem I am having with my '09 S211, and wondering if anyone else has solved this. Googling shows a few instances of this being a problem for others, but no shared solutions.
So, the rear seat interior ambient, and main 'door open' lighting only works maybe 1% of the time. Reading lights work fine. No combination of rear dimmer button, or front overhead console button presses springs it to life, but occasionally, it comes on of its own volition and stays working for a few minutes. All other interior lighting is working perfectly.
Given the lighting occasionally works, I am ruling out bulbs and wiring. Investigating wiring diagrams in WIS show the lighting is controlled by two modules, 'Overhead Control Panel Control Unit' and 'Rear Signal Acquisition and Accumulation', i.e. the rear SAM.
I have scanned the car for faults with iCarSoft, and the only persistent fault is on the rear SAM module - P9078 Communication with the component H3 (alarm signal horn) is interrupted. iCarSoft shows an 'Upper Control Panel' which may be the same as the Overhead Control Panel in WIS, that has no errors.
My gut feel is a faulty/failing rear SAM, but if anyone has managed to solve this previously, please do share how.
Thank you,
Martin.