blaSSt

2012 Grand Sport. Driver front turn signal comes on but won’t flash. All Filament bulbs no LEDs. Turn hazards on 3 corners blink but not driver front. Right turn signal, front and back blink normal. Left turn signal on blinks fast in rear, front constant on. Have tried 3 different bulbs in the front left all with same result. Any suggestions?

blaSSt

Additional info. Volt meter in front left socket. The constant on hot reads 12 v. The flash hot 0 v. When tried on right side see voltage bounce with blinking.

4SUMERZ

Could be a bad socket on that side that will not work, or a weak ground wire. Check the wiring going to the socket as per the attached diagram, incl ground wires.
Also check the bulb for the side marker. That may be bad on that side, which may affect the DRL flashing.
Circuit/System Description
Ground is applied at all times at G201 to the turn signal/multifunction switch. The turn signal lamps may only be activated with the ignition switch in the ON or START position. When the turn signal/multifunction switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the body control module (BCM) through either the right turn or left turn signal switch signal circuit. The BCM then applies a pulsating voltage to the front and rear turn signal lamps through there respective voltage supply circuits. Ground for the left front turn signal lamp is supplied at G101. Ground for the right front turn signal lamp is supplied at G102.

Martinp

We’ll, I had the same problem on my 99. I found out on my Cadillac that all exterior lights depend on the draw to function correctly. I found a backup light bulb burnt out and changed that one and turn signal then worked.
I checked backup lights on my C5 and found one burnt. Replaced that one and front turn began working normal. Go figure. Just my two cents.

FatsWaller

Well, this thread is 5 years old, but since you mention backup lights, I replaced mine with LEDs which presumably have way less draw than the incandescents, and my turn signals all continue to work correctly.

Martinp

The original thread I was responding to was 5/2024. My lights are also LED. I believe the idea is connectivity and not load. But what do I know. Can’t argue with success.