Expert: Robert Summers - 9/27/2008

Question
1997 Chevy Z71.  Couple months ago replaced left rear taillight circuit board, no problems.  Recently had to do the right side circuit board.  Lots of problems since.  Initially when the right blinker was turned on, it drew alot of power as all the lights would dim with the blinker as it flashed.  Was planning on looking into this weekend.  Now it's gone haywire.  I'll try to give a rundown of all the lighting problems.  Both tail-lights work just fine.  (All the following problems are for the rear lights only)  No brake lights and both blinkers have now stopped working. Hazards started working when I played with the switch (had to pull up on it) BUT they only work when I push the brake pedal.  Now I can't get the hazards to go off. (Had to pull the hazard blinker thing under the dash)  So I know the hazard switch is now probably bad, but the problem occured before I tried turning them on so it's got to be something else.  When I tried to diagnose the problem the other night I found that previous owners (used car lot) had stuck a 30a fuse in for the blinker.  (It only requires a 15 I think)  So out of curiosity of course I tried a smaller fuse (didn't have a 15 handy so plugged in a 20), of course it blew rather impressively when i turned on that right blinker.
Any suggestions, starting points????

Answer
Hi Carroll.... well there could be a bunch of problems....right side circut board... was it new or used...try it in another car and see if it does same thing.if not you will need to check the wiring to that side...start at the signal switch and work your way back...look for frayed wires  going to ground .... check the signal flasher for a short to ground... hope this helps