Signals Flash Too Fast - Yet All Lights Working

I didn't see where you changed the flasher for the blinkers under the dash, that may help.

Darn, I forgot to add that to my list Rowe Fast. Yes, I've been on this for over a week. Flasher was changed out on day one. But thank you for your wise observation, query. :)

Ok, the best I came up with from my sources, would be to try a heavy duty flasher. Seems when you add more lights the faster they flash, so they make a heavy duty flasher which would slow them down. Worth a try...

I had the same problem - Left hand side, rear. I tried everything! Here's what I found: If the signal on the dash is flashing fast, it means that the (high- tech) flasher unit under the dash is getting power, and sending 12volts out, but has detected NO resistance on that line. So it flashes fast (for some reason). There's a direct wire (mine was yellowish) from the flasher all the way to the bulb. After I metered the pins on the back of the flasher unit and found the one that was sending our a signal, I cut that wire near the flasher and used straight pins and an extension wire to start ohming the line all the way back. Even though the wire bundle looked GREAT and clean I found my wire was broken under the drivers seat, in the harness channel. Rather than remove the seat and all, I just fed a new (heavier gauge) wire through the channel and wire nutted it to a place where I had conductivity to the back bulb. Working like a champ now. Seems GMC did use the best of wiring as the wire was brittle when I worked with it. No wonder it broke. Good luck!! It's all fixable --- Btw: don't forget to splice the wire at the flasher back together. =o}

wrong turn light soket

There is a resistor behind the left headlamp that needs to be replaced. I had the same problem and almost pulled all my hair out before I found the problem

where did you get the resistor from? i checked all over