GM Repair Problems? Ask GM Repair Expert Now.
Hello and welcome!My name isCustomerand I can assist you with your question.
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Was anything replaced for this issue up to this point?
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Would you like a wiring diagram of this circuit?
Thank you for that information. One minute while I pull up your vehicle.
This problem you are experiencing is most likley a faulty bulb or a faulty socket allowing voltage from the running light circuit to backfeed into the left turn signal circuit. Sometimes there is corrosion or a wiring issue at or going to the socket causing this problem as well. But usually you replacing the left rear bulbs (and possibly sockets) will do the trick.
Ok, one of the LED bulbs could be bad leaking the voltage from the running light circuit to the turn signal circuit.