1997 Blazer 4.3 Vortec 4x4 four-door Whenever I turn my ignition key the engine will turn over but will not start. No dashboard lights, no running headlights, But if I turn on the headlights sometimes this seems to activate something and it will then turn over and start. Yesterday morning I also unplugged and reconnected the connector that comes off the Pos. Battery terminal, I did this with the ignition key on and this seemed to cause power to go to the ignition and I was able to start the vehicle. Please help it is very cold in Pa.

 

When it does turn over is it slow and weak or is it back to the way it works when everything is fine by cranking fast? Have you tried starting at night or only in the day? I.e. are the lights off or just so dim you cannot see them?

I ask as in extreme cold, the chemical reactions in the battery will be slowed down and turning on the headlights causes these reactions to occur enough so that the electrolyte is heated a bit, making the battery work better. This is even more the case for an older battery.

 

I think I may have found the problem. After doing more research and reading some other related post, it is probably the ignition wire harness. It looks like this is a common problem with Chevy vehicles from the early 90s - early 2000s. Thank you for your reply.