3360287 - K91 INSTRUMENT LIGHTS / LIGHTING DIMMER NOT WORKING

With the ignition ON and the side lights on, the instrument lights up, but the brightness remains constant when the controls are adjusted.
The brightness dimmer control is directed to the instrument panel node.
Results of the tests
1CHECKING WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the diagnostic equipment and check panel light dimming in active diagnosis mode.Continue to Step 2Dimming does not workReplace instrument panel Op. 5560B11
2CHECKING ELECTRICAL EQUIPMENTAll OKProblems metOperation
Check the condition of the wiring between control button on LH panel and instrument panelContinue to Step 3Wiring broken or short-circuitedRestore the connection See   E2530  INSTRUMENT LIGHTING
3CHECKING CONTROL BUTTONAll OKProblems metOperation
Check operation of the dimmer control buttonContinue to Step 4Button faultyReplace the LH control panel
4CHECKING CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentFault persistsSearch for the fault starting from another symptom'