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Any tips on getting the best out of WIS?

MJJ

Active Member
Joined
Jan 13, 2020
Messages
135
Location
Wiltshire
Car
'09 S211 E220 CDi manual - 197k miles and counting
Afternoon all,

I have recently started using WIS, and without the benefit of the no doubt lengthy dealer/manufacturer training courses, it is of course a daunting tool to get into and start using.

I am trying to diagnose intermittent only working in my car's ('09 S211) rear ambient, and dome lighting. So, I search WIS trying to find wiring diagrams for my VIN.

The best I can do is the following wiring diagram, which shows the relevant lights (E15/3) being controlled by N70 - Overhead Control Panel Control Unit.

I am then trying to find where that is located in the car, whether it just means the light unit itself, and whether that N70 OCPCP is ultimately controlled by one of the SAMs in the car. I cannot get any further useful documents to help find locations, or wiring diagram to the N70 OCPCP.

Any tips from WIS users on how you would go about trying to do this sort of diagnosis? Would you keyword search, navigate the various tree structures to try and find a diagnosis document, maybe look for block schematics rather than wiring diagrams?

Thanks for any tips people can offer,

Martin.
 
Checking in for any tips, I just got it too and can't get my head around it! I can just about find parts but it's supposed to link to instructions too?!
 
If you start EPC from WIS or WIS from EPC, it will normally get you to the relevant subsection.

Alternatively, search EPC for the part, as it named in the WIS page - works sometimes, although MB have propensity for giving five different names to the same part - e.g. tailgate / rear-end door / lift-gate, etc ...
 
Thank you for the inputs all, I have read the instructions @55AMGCLK linked to, and tried triggering EPC from WIS, and vice versa.

I think my main challenge here is that these are CANBUS cars, so wiring diagrams just show physical connections into modules, they don't seem to show the processing that occurs within the modules and whether a particular pin on a module can be probed for 12V, like in a more simple electrical architecture.

It looks like the interior light I am trying to diagnose is fed by the boot mounted SAM, but it does not look like testing of the SAM is possible for a DIY-er. WIS does not seem to suggest the part needs coding, so I may be tempted to pick up a used one and try that.

I do hate doing diagnosis by throwing parts at a problem, but these are complex systems.

Martin.
 
MJJ, I would recommend you that you get the car scanned on a diagnostic machine or you buy one. The Icarsoft MB II will be suffix for most and will scan the SAM’s for errors and clear them if they are non persistent.

There is a post on this forum for a group discount on the icarsoft scanner.
 
Thank you, and good point. I bought the iCarSoft CR Pro as part of the group buy, and cleared every error on the car a couple of days ago. No improvement to the lighting issue, but will re-scan to see which SAM errors have returned.

Martin.
 
MJJ, I would recommend you that you get the car scanned on a diagnostic machine or you buy one. The Icarsoft MB II will be suffix for most and will scan the SAM’s for errors and clear them if they are non persistent.

Just posting back to close this one off, now I have scanned the car again. There is one persistent rear SAM fault, P9078 Communication with the component H3 (alarm signal horn) is interrupted. I don't believe this is related to my interior lighting issue, but will start another thread to see if anyone happens to have solved something similar in the past. My searching shows a number of people having the issue, but not posting a solution alas.

Thanks again for your help @55AMGCLK.

Martin
 

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