The other day going home noticed that my left turn signal was slow and eventually stopped working. Headlights, Right turn signal, 4 way flasher, Brake lights all work. Next morning it was fine but again in the afternoon it acted up again. I'm not electrically inclined so any help would really be appreciated. Thanks

 

First try changing the bulb.

 

If the new bulb doesn't fix it you are probably looking at a new flasher relay. They are inside the truck on the driver side fuse box. Some years have it installed in the back of the box for some reason. The 4 way flasher and the individual signals are separate functions on the relay so its probably just that.

 

The factory set up is designed to light up when the bulb is out. It may have burned out or the ground failed. It could also be your flasher relay went south. If you replace a thermal relay with a solid state one, your lights will work even if one bulb is burned out. You'll have to start doing a safety check from time to time.

 

I changed all the bulbs front and back. They did look all burnt. With the new bulbs they seemed to work perfect but I noticed that after about 10-15 minutes of driving they start to blink slowly. I will replace the flasher relay and let you all know. Thanks again all