I have a 1993 C1500 stepside. The turn signal fuse always blows. the signals do not have to be in use for the fuse to blow. I have ruled out the harness from the firewall to the rear by disconnecting it at the firewall. I found as many grounding points as I could find and roughed up and made ugly to assure a good ground. fuse didn't blow for about a month, then it started blowing again. I have replaced the switch located at the base of the steering column. still blows. I am in the process of running a separate and independent ground wire from each grounding point to assure that there is no break in the original wire. so far, fuse still blows. I do not know where all of the grounding points are located. does anybody have any clues to the cause of my problem? any ideas on how to cure the problem? thanks in advanced of any suggestions given.

 

I had the same problem a few weeks back. As it turned out, it was my 4 pin trailer harness that collected water inside the rubber cap, creating a draw that eventually overtook the fuse. I ended up replacing my turn signal switch and all my fuses and all is well.