I got a 1993 blazer 4.3 cpi with 188,xxx miles. the past couple days i started to notice my speedometer wasnt reading rite and everytime i pushed anything electronic it make the needle for the speedo jump. And when i slow down to stop the speedo takes about ten seconds to drop down from when i stop but if i put m headlights on it will spike again...But i just shut the truck off and turn it back on and its back to normal. But now its starting to act up again. when i started my truck five seconds later it completly shut off. it wouldt crank but it would buzz.I had a friend jiggle the bat wire and my idiot lights come on and off but then they stayed on like there suppost to when you first start up. start driving and speedo acts up and my lights dim and flicker and the radio resets. then it shuts off again but miraculasly it started back up ad the prooblem didnt come back. I just want to know what im dealing with here if its the battery, pcm, or somthing stupid. any help would b nice

 

I believe i figured it out. The PO of my blazer put in aftermrket bulbs but never upgraded the harness... now the connecter looks all burnt and melted so i unhooked it and it seems to be wrkng perfectly. guess i now have tto invest in a heavy duty headlight harness. hopefully this will help out anone who has sort of the same problem. Just look around, youll never know what ya find