Warning dash lights flickering

MADDMAN

MEMBER
2008 AUDI A4
2.0L
4 CYL
4WD
AUTOMATIC
113,000 MILES

Starts and runs. Turn key to off position with key in ignition, the warning dash lights flickering and relay clicks in ECU plastic box in engine compartment. Pull key out of ignition and warning lights stop flickering and relay not clicking. I replaced ignition switch on end of cylinder lock housing. I cleaned battery post (+/-). Cleaned many ground connections in engine compartment. Not sure if the ignition lock cylinder is the problem, or the starter relay in ecu plastic box is going bad. Or the wiring harness to ignition switch has crack in insulation touch ground or another wire.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

Every thing you just listed is a possible cause. I would have thought the switch was the issue as well but if that is replaced then I think we have a wiring issue. However, we need to start testing these things one at a time.

One thing I would try first is to swap the relay that you hear clicking. Clearly a relay is easy and could be the issue. If that is not it then we need to load test wiring to ensure they can carry the current needed.

Are you familiar with how to use a headlight bulb to test the ability of a wire to carry the current? Basically you are taking a bulb and putting 12 volts to it to see how bright it is and then compare that to this circuit. Clearly this is subjective but if it is dim then the wiring is the issue.

Let's start here and go from there. Thanks

https://www.2carpros.com/articles/how-to-check-wiring