Hey everyone I am having a problem and it has me completely lost and have no idea where to go next. I have a 2007 silverado nbs. Intermittently my truck ...

Hey everyone I am having a problem and it has me completely lost and have no idea where to go next. I have a 2007 silverado nbs. Intermittently my truck will not start. I very first suspected the starter so i went there first no fix. next i went with ignition switch no fix. new key and ignition cylinder no fix. read online it was a ground issue. literally ran all new grounds from ecu you name it and still no fix. I need help. Now sometimes it fires right up no problem at all and i can drive it with no issues what so ever. other times i start it and it cranks but does not start. other times i start it it fires right up but my gauges are going crazy and my locks are cycling with the truck just sitting in park and its like the ecu doesn't know what gear the transmission is in. put it in reverse and the rear view camera will switch on and off as the gauges bounce all over. while that happens i have noticed the line under the gear indicator in the cluster is gone and as i switch gears the trans will switch but it does not show up in my cluster then sometimes it starts and all the gauges and everything is great and out of nowhere while driving the gauges act stupid again rpm tach jumping everywhere speedo all over the place and again the line under gear indicator is gone. sometimes when everything is going great and u think you have fixed it you stop somewhere shut truck off and it wont start back up....no crank no start no nothing. turn key on and all lights and everything come on as they should, turn to start and it doesn't make a sound at all. Had it towed home the other day and sure enough right as it gets dropped in my driveway i turn key on and notice the line is back under gear indicator and the truck fires right up. My next suspicion is the neutral safety switch but I'm tired of spending money on something that doesn't fix the problem and the neutral safety switch doesn't explain gauges going crazy and jumping all over the place if they even do anything at all sometimes they just sit there dead. the battery is brand spanking new as well and when all the gauges are going stupid the volts/battery gauge is the only 1 that is always working. some1 please advise me where to go next

I would start by checking your battery cables for corrosion on the insides of them. Check the mega fuse by the battery for good contact and make sure the connections are all tight. I have read many posts that the cables are the problems as the corrosion is on the inside of the cables were you wont see it. If everything looks good there i would try the fuse box on the drives side under the hood and look for any corrosion on or around that area. good luck.

+1^^^

I did as u mentioned and checked all battery cables and replaced the positive cables with 0 guage oxygen free copper wire including positive wire to alternator. Added some grounds replaced some grounds and cleaned up contacts on all the other grounds i can find. Pulled fuse panel and everything really looks great didnt find ant corrosion or anything that was worth even batting an eye at. Replaced mega fuse and cleaned those contacts as well. Still having same issue. Any other ideas? Im wondering if maybe i just have a bad ecm?? At this point thats all i can possibly think of

I would suspect the BCM (body control module). Sounds like it may be freaking out. I don't know of a great way to test but what I would probably try is reading the data from the computer. What I mean is, data log the computer as you idle and as you drive. Look at the output numbers and look for trends. I noticed on my VW, for example, I was getting a reading of 400F from the temp sensor. In my case it was a ground, but it could be the computer not interpreting the inputs correctly.

Otherwise, I would keep checking with the grounds and possibly the positive leads. Have you looked at the fuse block under the steering wheel?

Removed the fuse block under steering wheel today and checked all wires and connections. Saw 1 ground that i didnt like all that much so i wire brushed body and put new terminal on. All positive leads are new. Followed wires as far threw dash as i could and out the firewall everything looks great took it for a drive and just a few minutes in guages go crazy amd locks start cycling. Once it starts doing it it doesnt stop until u shut truck off and let it sit for awhile then you can get in once its cool anf start driving again. Its like it is on a timer. If i take the same exact route everytime i change something amd take it for a test i could almost narrow it down to the square of concrete in the road where its going to start acting crazy. Once it started acting up today i quickly pulled over and started taking reading with my volt meter and everyrhing is good no matter where i pull a reading from im getting +14 volts. Not that it matters but the truck is garage kept and not daily driven at all. The body still looks new there is not a spec of rust anywhere nor any corrosion anywhere what so ever even the frame looks like it just rolled off the showroom. Havent received ecm yet but im going to put it in either way so maybe from there i get the BCM you suggested. I dont know at this point i feel im going to just keep buying stuff til it stops doing what its doing

Sure sounds like a ground or connection issue with the battery.
What happens if you take it for a test drive on a different route? Does it flake out after the same time driving? I am just wondering if you are not driving past some kind of source of electrical or signal interference that is causing it. Like something setting off your door locks as if someone was pressing a remote key fob. That is just a shot in the dark, but really it sounds like a ground or battery cable issue.

Doesnt matter which route i take it will start acting up sometimes it takes longer then others but after beating myself up on this i have also replaced the battery terminals. The negative terminal i replaced with a 6 way 0 guage terminal from a stereo shop and have added 5 0 guage ground wires from battery. 1 to engine block 1 direct to starter 1 to ecu and then 1 to left and right side frame rail and like i said i replaced the positive leads from battery with 0 guage ofc wire because i was so convinced it was a ground power issue. Doesnt really matter where i take an ohm reading either it all reads about .1-.3 so its getting a good ground. Like you are stating i then started checking all connections in fuse panels following wires all the way back to tail lights as far as i could go in every direction. Now this all being said all this crap started when i installed a new battery but i did arch the battery out when installing and im wondering if when it arched out the jolt of energy ran through the ecu or maybe the bcm and jacked it all up. I really appreciate your responses so if you jave any other ideas please shoot them my way but i am going to jist keep heading down the path of trying to find a loose connection somewhere or something. Only reason i dont beleive its a loose connection is because when it starts acting up ot doesnt stop and i would beleive if it was a connection issue it wouldnt be so frequent and like i said if it was a connection u would think it would do it then stop and do it again as u keep drivong because the connection is going to keep coming and going but once it starts it wont stop until you shut truck off let it cool down then for awhile like couple hours then start back up. As of recently i have not had any more starting issues tho it seems to start everytime

OK, now we are getting some more info.....New Battery!!
I understand the possibility of arcing something or whatever when swapping batteries, but did you ever think that maybe the battery itself is jacked up? This would be an easy check. Just swap in a known good battery from another vehicle and take your little test drive. If it jacks up again, then you can rule that out. If it doesn't, take the battery back and get a new one. It really does sound like a battery/cable/power issue.

Didnt think of that but good thing i have 2 more chevys in the driveway. Time for a battery swap and test ill let you know. Thank you