Left Turn Signal Stays On

[dannyldixon]

I have 2003 Silverado 1500 5.3L Automatic. Recently, the left turn signal has been staying on all the time, unless the brake pedal is depressed. When I press the brake pedal, everything works as it is supposed to. When the pedal is not pressed, the left turn signal in the front, rear, mirror, and instrument panel remain on all the time.

 

I removed the fuse for the left turn signal and the light remains illuminated. I suspect a short, so I have tried to isolate the location by removing some fuses. I have removed the fuses for left and right turn signals. I have removed the fuses for the front and rear park lights. Still the left turn signals are remaining lit.

 

In a further attempt to identify the source of power for these lights, I removed and replaced the fuses from the fuse panel by the driver door one at a time. I found that the problem goes away when I remove the 10A fuse labeled "Brake".

 

I have looked at the "typical" wiring diagrams included in the Haynes manual, but I am not sure that these wiring diagrams are entirely accurate to my model.

 

Are you aware of any common problems that produce this issue or have any advice about where to look for a potential short that would power the signal lights from the "Brake" fuse.

 

With the "Brake" fuse pulled, I do not have ABS and the ABS and Parking Brake warning lights are on with frequent dinging of the bell.

[dannyldixon]

Any chance at an exterior lighting wiring diagram to confirm that removing the park light and turn signal fuses should isolate the lamps?

[rockcrusherrevived]

one of your signal bulbs is burned out

 

 

I have 2003 Silverado 1500 5.3L Automatic. Recently, the left turn signal has been staying on all the time, unless the brake pedal is depressed. When I press the brake pedal, everything works as it is supposed to. When the pedal is not pressed, the left turn signal in the front, rear, mirror, and instrument panel remain on all the time.

 

I removed the fuse for the left turn signal and the light remains illuminated. I suspect a short, so I have tried to isolate the location by removing some fuses. I have removed the fuses for left and right turn signals. I have removed the fuses for the front and rear park lights. Still the left turn signals are remaining lit.

 

In a further attempt to identify the source of power for these lights, I removed and replaced the fuses from the fuse panel by the driver door one at a time. I found that the problem goes away when I remove the 10A fuse labeled "Brake".

 

I have looked at the "typical" wiring diagrams included in the Haynes manual, but I am not sure that these wiring diagrams are entirely accurate to my model.

 

Are you aware of any common problems that produce this issue or have any advice about where to look for a potential short that would power the signal lights from the "Brake" fuse.

 

With the "Brake" fuse pulled, I do not have ABS and the ABS and Parking Brake warning lights are on with frequent dinging of the bell.

[dannyldixon]

I checked all of the bulbs and found that the very small bulb at the bottom of the tail light assembly on the driver side was discolored and not lighting up. I removed that bulb from the driver side and the passenger side and the behavior was the same... The left signal always on and the right signal correct. I put the good bulb in the driver side and it barely lit up. So, I checked the sockets with a volt meter. The voltage drop across the socket on the driver side was only 1.23 V. The voltage drop across the socket on the passenger side was 9 V. I checked the voltage to ground on each terminal of each socket. The voltage to ground was is below and I have indicated the color of the wire going to the terminal in the socket.

 

Driver - Blue ~ 8 V

Driver - Brown ~ 9 V

Passenger - Blue 0 V

Passenger - Brown ~ 9 V

 

Now, I need to find out why there is voltage to the blue wire in that socket. The wires pass through a hole the body panel behind the tail light assembly in a plastic sheath toward the frame. A thunderstorm prevents further investigation tonight.