2004 Silverado 2500HD gremlins

I post this here because I know the hive works in miraculous ways and he's about ready to just drag it to the boneyard...

So my boss has been having issues with his 2004 2500HD. (gas)

Put the key in, dash lights up. No start. Intermittenly. Like, this winter it did it off and on for a week. Then three months no problem. Lately it started doing it again to him.

He's replaced so far: starter, alternator, ignition cylinder, New key. (and done the home self program.) main power relay.

At first if he got out and pushed on the fuse box (on the main relay) or pulled it out and put it back in; the truck would start up right after. Lately this trick has been less and less effective. He has pulled up the fuse box and states that no wires look burnt or damaged.

The main power lines that come to the relay show 12v. the smaller wire (from key) shows no voltage. therefore no start.

grounds would be suspect

there are prolly no less than a dozen on that truck

Put the truck in neutral and see if it starts. There's a good chance the neutral safety switch is dying. If it doesn't think it's in neutral or park, it won't send power to the starter relay, just like you're seeing.

These have some known ground issues. Not as bad as the NNBS trucks but certainly bad. Sometimes it's the connections to the chassis, sometimes it's the ground harness itself. Need some time with a voltmeter and a dremel/wire wheel and some good dielectric grease.

If he pushes it over to my house, it would make an excellent engine donor!

But yeah, grounds or neutral safety switch

I'll give him 300 and a grilled cheese sandwich.

No help otherwise.

I'm fairly sure he's tried neutral. (he's a PE mechanical engineer so the easy stuff's been tried.)

He reaaaally does not want to go through every ground...

Does that main power relay have a ground associated with it? or is there just the general ground for the box?

I've seen a Yukon from around 04 with intermittent no crank from a faulty ignition switch.

The problem with these sorts of problems is that they're essentially undiagnosable without a crap load of diagnostic time or just luck. Swapping out suspect parts (which he seems to already be doing) is the low labor attempt at proper trouble shooting. The reason I suggest grounds/fuses/connectors is because it's an all labor proposition for DIY car guys that can solve a LOT of problems without costing money. Actually paying someone to chase electrical issues is expensive.

I was hoping someone would have done this and could bury the question with truth. Googling (which he and his son have done) comes up with a bunch of hack "this fixed it for me but is not a surefire way" bull.

You know, how random people know which ground wire to fix an issue on such and such a car.

You'd think with the number of these trucks someone would have figured out what EXACTLY causes this apparently very well known issue.

We really thought a wire was loose under the fusebox but when he pulled it out he said everything looked great. My thought was that maybe however the fusebox is grounded out is not done right and so other issues are arrising.

i.e. the other day when getting out to try pushing on the fuse box to get it to start the truck started acting like the key was in the ignition with the door open. no key was in teh ignition... then the dash died on him that same day.

I almost feel like the whole wiring harness is suspect.

Pull the steering column apart. Pull the ignition switch. Find out which wires in the connector are what. See if things behave as expected when power is applied to those wires. If everything works, then the issue is probably the switch.

See OP. Switch has been replaced already.

Though it could be the connector.

Now im just hoping my "new" truck doesnt develop this issue too. I agree theres alot of chevy truck info out there but about 25 ways too fix each issue.