Need some helpful advice. My 1999 silverado1500 wont start. New battery shows +12.4 volts. The truck is an automatic with about 258000 miles. Transmission was replace at about 225000 miles. I have no power anywhere. Turn the key and nothing happens, no buzzer, dash lights, no security or waring indicators, nothing. The day before everything was find, however, I recharged my a/c unit (found leaky valve) last night, and today nothing works. I don't believe there is a correlation between the a/c the whatever is going on now, however, I could be wrong. I'm thinking the problem is the neutral safety switch but I'm looking for any solutions out there. I have moved the shifter lever to neutral and still nothing works. Its as if there is no battery in the truck. Any help would be greatly appreciated.

 

Mine just went trough this. I found my positive battery cable had come loose and was just bouncing off of the battery terminal causing power here and there. I tightened it and it came right back to life!

 

The neutral safety switch would not cause everything to go dead. It sounds more like a loose or bad battery cable as stated by Eggie329.

 

I just changed the battery, that's a great place to start. Thanks.

 

See if you got power to your lighter if not back trace it
from battery to fuse box the ecu then whatever needs power no power to all easier then no power to one thing lol

 

Even though you just changed the battery doesn't mean it can't be the problem. I dealt with this same problem for a month before I figured it out. The battery terminal wasn't connecting right. I had a new battery but no power anywhere. You might not be getting a good ground somewhere either.

 

Thanks for the input. Got it fixed. Negative battery terminal was not making contact with screw in stud.

 

hello our truck has the same problem. My boyfriend already checked the voltage of the battery with his volt meter and it was 12.8. The truck will still not start and it is not making any noise at all, but the internal lights come on and when he turns the ignition all the lights shut off. He also checked the fuses and relays which were good.Also when we press the horn it shuts off the lights too. Can someone please give us good advice on what might be wrong with the truck.

 

Same thing of what I told him. Take off your the terminals of the battery, sand them down or pour some coke on them then put them back in and make sure there tight