Intermitent cranking problem

03 Trailblazer, 4.2 L, 54359 miles. Will crank and start. Went in the store, nothing. Had interior and dash lights. Let it sit and cranks and starts fine. This has been going on for several weeks. Considered possibilities: Ign. switch, security sys., neutral start switch, and ?????????. Anyone have a similar problem before or currently ?

Thanx in advance. :grinyes:

No quick fix here, yes could be ign switch, if no start see if 12v to solenoid if not get to starter relay, switch with another one, l/s relay box under hood, this will require on the spot electrical checks back from the starter to the relay to the bcm to the ign key cylinder.

No quickie here either. Maxwedge has that starter sequence down. I'd look at something else ahead of it, though. Inspect the battery and connecting cable ends carefully. If the battery is leaking around a post it could be getting too hot, ready to fail. A leaker can trash your cable end, too, to where conductivity or ground becomes intermittent, not to mention hard on the electrical system. A battery is simple enough to replace - just get one with equal or better CCA and steady output than OEM. You can get temporary cable end fix clamps whether side post or top, but if a cable end connector is corroded or burned the best fix is to replace that cable. Good luck.

I agree....from experience, a bad battery connection will cause all kinds of intermittent problems. Check your connections, and get some battery terminal cleaner, a wire brush, and new battery bolts if they are pretty corroded.