GM-GMC: Electrical Turn Signal Problem, left turn signal, signal problem

Question
Hi, I have a 1988 Chevy one ton, 6.2 diesel, 2 wheel drive, auto, with tilt steering. Problem is when I turn on my headlights my left turn signal turns on. I've replaced the ignition switch, headlight switch, searched for loose wires, grounds, shorts...fixed a few but still haven't solved this problem. BTW, both turn signals do work. I'm getting ready to pull the steering wheel and replace the guts in the column, as my brights switch doesn't work anymore and my tumbler is slipping. Just wondering if this problem could be something more simple, like a turn signal fuse or? Any suggestions?  

Answer
Try changing the switch in the column for the headlight dimmer.  I believe that you will find it part of, or running near, the turn signal wiring (which also runs in the steering column).

There could be a defect in the switch or wiring in the column that is causing your problem.  Be careful when installing the new switch as there is not a lot of room for the wiring and installing it can chafe the insulation.