Case Study: 2012 Jetta, front end collision, left marker lights innop



Ross-Tech Employee
Staff member
Jan 29, 2014
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2012 Jetta, left front end damage. New left headlight has been installed and some minor body work performed. There are marker lights in the headlights and tail lights. The marker lights on the left side, front and rear, do not work. Both right side marker lights are working. The J519 has this code:

03431 ASAM-EN-9999 Activation of left parking light: short to ground.

When the code is cleared out out, the left marker lights will light up for a second or so, then go back off. The fault code returns. Front end is still apart so able to remove the headlights. Take the left headlight and plug it up to the right side of the car, the marker light works just fine. Put the right headlight and plug up to the left side, same issue, no marker light.

Go to the tail lights, removes bulb holder and unplugs... told the front marker light just came on. Looking at the tail light bulbs, they look brand new, one single filament and one duel filament. Remove the dual filament and see if there are one or two contacts in that holder. Has to struggle to get the bulb out, really jammed in there... finally gets it out, 2 contacts. Bulb pops right back in with out issue. Plugs it back up... and now both front and rear marker lamps are working, code clears out.

So some body shop guy, for reasons unknown, replaced the bulbs in the tail lights and was unable to correctly install a light bulb.... thus the J519 was all like "phuc dis" and shut down the circuit. We suspect both contacts of the bulb were mated to a single contact of the holder, so when the J519 went to power that circuit, more current was being pulled since there was "an extra bulb" on there.

Fixing a car is easy, diagnosing the car on the other hand.... :banghead:


Jan 29, 2014
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Montgomery, NY, USA
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Yeah well in the old days in early 89 Passats came out the auto trans lock wouldn't work when some idiot did this and the cars would commence to be towed in.

No OBD or DTC to go by back then either........

Common sense but not to anyone without basics and to check the obvious!