My truck will not start. I have a 2003 silverado SS. The last time I drove it was Thursday and it has never given me any trouble like this before. I parked it Thursday and have unlocked it a couple of times to get stuff out of it but today I go to start it and it won't turn over... I played with the key alittle and it finally turned over a few times but still didn't start. Then I noticed the fuel pump wasn't priming so I checked all of the fuses and relays and nothing was bad or out of the ordinary (even gave them all a couple taps). Then I put 12v to the fuel pump prime slot on the fuse panel and the fuel pump came on and sounds normal. Then I try to start it again and still nothing, no click sounds or anything. Then I noticed it will only turn over if I shut the doors and lock the truck then unlock it and try to start it but it will only turn over until I let off of the key and then it will not turn over any more after that until I repeat the process..
I have not touched anything under the hood in weeks and the truck goes months without being started and has never given me any issues before. Any input is appreciated!!

 

Sounds dumb but wiggle the battery posts. Sometimes they get corroded and cause weird issues like that. Otherwise start the diagnostic chain, fuel, spark... fun fun.

 

+1

I had to replace an entire ground cable before due to corrosion.

 

My 99 gives me issues with the terminals, however my 02 z71 had two bad battery's. What I found is the cranking amps were not there. Fuel pump issues also- put a battery charger on 50amps to help out no luck but it would turn over okay but no fire, took my fishing trolling battery with jumper cables it fired right up- so I put battery in it did the trick.
Good luck