fuse keeps blowing under certain conditions

[johncaravalho]

THE VECHILE: 1997 sierra 5.0
THE PROBLEM: Left turn signal works as long as you don't touch the brake and ignition switch is on, however if you start the truck and turn on the left turn signal the fuse blows


the symptoms have caused me to change a relay and the hazard signal relay buzzes when the blinker is on in doing all this i descovered several melted wires was able to apply heat shrink to the wires and cover the chafing that had occured however am wondering what caused the melting to occur and the other symptoms have torn the dash apart