S.M. Auto

VW Passat – When lights are out, It’s not always just a bulb

What’s the problem?

A Volkswagen Passat came in with a warning light on for a bulb out and a non-functional Daytime Running Light (DRL) system. The customer had already replaced the bulbs, but it hadn’t made a difference. The only other information we had was that the car had been in a minor accident with some light panel work done, but the warning lights didn’t appear until well after the repairs

Visual checks save time.

A quick look at the front of the car and I noticed a slightly ill-fitting bumper. Looking through the grille, I could also see a wiring loom which was running on the wrong side of a panel with the insulation torn.

The next step was to expose the loom and see what was happening inside. As suspected, there were broken wires.

My next step was to verify that the exposed wiring had the correct powers, grounds, and signals. I performed this test using a simple test light and a multimeter to prove out the integrity of the circuit.

All the wiring proved to work just fine so its just a case of connecting these wires and the job’s done.

Conclusion.

I suppose the conclusion here is pretty simple, find broken wires and repair them – now everything works. But the lesson is looking for clues where previous work was carried out. It’s unfortunately very common to find problems like this that were created during past repairs.

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