Flickering dashboard/switch backlights

[Ross Gridley]

Hello folks

Our company has a 2010 T5 Transporter that has a problem with flickering instrument/switch panel backlighting. On occasions the instrument cluster backlighting will also flicker.

I've checked the fuse panels and all seem OK. The loom is securely fitted to the headlight switch, as too the brightness control - although the brightness control has no effect.

I removed the brightness control hoping it might have been just a dirty variable resistor but it looks like there's a chip inside too. Are the backlights actually LED's and the brightness controlled by pulse width modulation?

Not having a wiring diagram I probed the brightness 3 pin connector and found the +12v then bridged it to one of the other pins; that brings on some of the backlights, not all, but at least they're not flickering.

Has anyone had similar problems? If so I'd appreciate and advice/suggestions (and even a wiring diagram ).

TIA

[LogicprObe]

This is what is says about the unit from 2010 onwards.

General description - dash panel insert
NoteThe control unit in dash panel insert -J285-, immobiliser control unit -J362- and the data bus diagnostic interface -J533- are integrated in the dash panel insert and cannot be renewed individually.
All warning lamps are fitted with light-emitting diodes (LEDs). No provision is made for dash panel insert repair. If necessary, the dash panel insert is renewed as a unit → Chapter.
Fault detection and fault display:
The dash panel insert is equipped with self-diagnosis to ease fault finding.
For fault finding, use the systems described in chapter “Vehicle diagnosis, testing and information system” in “Guided Fault Finding” mode → Chapter.