Volkswagen Repair: Electrical - Tail Lights not working, volt ohm meter, digital volt ohm meter


Question
My tail lights are not working, checked the fuses and replaced burnt out bulbs, still no joy. The brake lights, turning indicators, reverse and registration lights work.

Cheers

Peter

Answer
Hi there Peter;  Without knowing what model, or year of car, I'll go with the most popular...an A4 Jetta...1999, to 2005.  This problem could be related to the headlight switch itself.  Has anyone ever put a "European" headlight switch in the car for use with the factory fog lights, and the "parking" lights?  If so, there is a tab inside the switch that has to be bent over to eliminate the "daytime running lights" feature of all cars being registered in North America.  If this tab is not completely, and carefully bent over, it can cause damage to the headlight switch, and to the headlight/tail light circuit.  They are not all that popular a modification for Jettas, but GTIs, Golfs, and Passats have fog lights available as factory installed options in certain production years.  If it is not the switch, then the wiring requires a "continuity" check.  Use of a digital Volt-Ohm Meter is the best choice for this type of wiring check.  Consult a wiring diagram for the headlight switch, and figure out which wire/wires feed the tail light portion of the circuit.  Jumper those positions, or that position to one side of the meter, and then go to the back of the car where the tail light housings are located, and see what the resistance is in those wires.  Also check the tail light housings for damaged, or corroded, or tabs inside the housings that are not making contact with the bulbs.  This has happened mostly in New Beetles.  When you do any kind of "continuity" check on your wiring...keep your key in your pocket, don't power up anything in the car.  Let the battery in the DVOM provide the power necessary to test the resistance in the wires.
Happy hunting, Peter, Hope this helps you get started down the correct "path."