Strange electrical problems

Trying to help a friend figure out what’s going on with her 2014 Jetta S.

Here’s the situation in her words:

“Epc and traction control light come on randomly. While driving it’ll go between the epc/traction control to the abs light and brake light. If the abs/brake light comes on, it’s harder to get the car to accelerate. Steering wheel gets slightly harder to turn when abs/brake lights are on and Doors lock/unlock constantly when abs/brake lights are on.”

“The other night, the lights lighting up the numbers turned off while driving and turn signal wouldn’t work. Lights would go off and come back on randomly. Didn’t affect the headlights at all. Just turn signals.”

Had her get a new battery since hers was very old. Didn’t help. Told her to reset the computer. Read some cases with similar circumstances that were bad ecm relay fuse and have been trying to figure out its location.


At any time did you think to see what the codes were before clearing them???


Electrical problem like a bad ground.

Had a car where the battery to chassis ground was failing. The battery to engine ground was good. There are no additional ground links. There was over 1 Volt difference from engine to chassis I believe. It would stall at idle. Ground imbalance can mess up a lot of things.

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Any idea how to track it down?

Yes, inspect the ground connections and make sure the grounded areas are less than oh 50mV from each other.

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Your idea to install a new battery was a good one. The symptoms are pretty consistent with low battery voltage. The problem however may be a faulty alternator, suggest to have that shop-checked.