Courtesy light control fault

[saskak]

Hi all,

I was recently checking Diagbox to see if everything is ok and got a weird fault recorded. It is BSI A4A1, "Front/rear courtesy light lighting control fault. Short circuit to positive local" (Permanent local).

The car is a Pug Partner (M59; 2007, 1.6HDi; 92bhp). The fault seems pretty obvious, but everything works alright with the lights, they switch on/off, etc., without a problem.
I thought there was a problem with a lamp that was behaving weirdly and replaced all of them and the fault is still there. I cannot also erase that fault. Not too sure where this lighting control module might be located, might have to check servicebox to see where the lamp control goes to.

I know tracing electrical faults is rather difficult, but if you have an idea I would really appreciate it.

[Zion]

There is a permanent live for manual courtesy lights "on" along with the variable one for "theatre dimming", a trigger from the BSI for the door switch plus a ground, all wires go to the BSI1.

My guess is the switch contacts for off/on/auto with doors is maybe corroded or damaged and the BSI can see the plain 12V is getting to the theatre output wire? A short between pins 2 & 3 for example on module 3010. Also could be the same issue but in a rear light, is your roof antenna leaking maybe?

Interior Lights:


  M59 Lighting 1.pdf (Size: 621.24 KB / Downloads: 21)


  M59 Lighting 2.pdf (Size: 621.24 KB / Downloads: 14)


  M59 Lighting 3.pdf (Size: 621.24 KB / Downloads: 8)

[saskak]

There is a permanent live for manual courtesy lights "on" along with the variable one for "theatre dimming", a trigger from the BSI for the door switch plus a ground, all wires go to the BSI1.

My guess is the switch contacts for off/on/auto with doors is maybe corroded or damaged and the BSI can see the plain 12V is getting to the theatre output wire? A short between pins 2 & 3 for example on module 3010. Also could be the same issue but in a rear light, is your roof antenna leaking maybe?

Interior Lights:

Sorry Zion,

I seem to have missed your reply. Many thanks indeed. The roof antenna seems to be alright and not leaking (as far as I can see), but I will probably have to inspect all the switches to see if they are all alright.

Many thanks again.

[saskak]

There is a permanent live for manual courtesy lights "on" along with the variable one for "theatre dimming", a trigger from the BSI for the door switch plus a ground, all wires go to the BSI1.

My guess is the switch contacts for off/on/auto with doors is maybe corroded or damaged and the BSI can see the plain 12V is getting to the theatre output wire? A short between pins 2 & 3 for example on module 3010. Also could be the same issue but in a rear light, is your roof antenna leaking maybe?

Interior Lights:

Yeah, there is continuity between pins 2-3, good call. I have to have a look at 40V BA to see if it is there as well. Probably chafing somewhere and these cables go around the whole car. Pulling trim around to trace it is something I really like to avoid.