Well maybe and I emphasize maybe. I went through last weekend and ran an extra ground. Currently the battery grounds the frame behind the fog lights and then again to the driver motor mount. Then off the back of the block just above the transmission bellhousing there is a braided wire that jumps to the firewall. That cable (best I can tell) is what grounds the electronics in the car. My theory was possibly intermittent ground to the bcm due to age. I ran a 10 gauge wire from the battery terminal straight to the braided wire on the firewall. That wire warms up as the car runs which tells me it's holding load, which makes sense since it's the ground of least resistance. My truck had been fine for a week and that fixed s few of my other gremlins as well. I also cut the eye rings on all the grounds I could reach and soldered new ones. That's where I am now. I'll keep you posted of any new occurrences if any.

 

Thought I would give an update. Last wknd I went through and did the same as you. Cleaned and reseated all the grounds I could reach. I don't drive mine until the wknds so wasn't sure if it helped. Started fine 16x in a row. Then this morning acted up again. I did not run the extra ground like you did so I may try that.
Been searching the web in the meantime for others with this problem. Saw a couple of posts on the Z71 forums abt it but no one ever really gave a clear resolution. I'll join/post up over there as well and see if I can get us any more info.

 

That is kind of disheartening actually, as mine has been working great since i worked on the grounds. I have driven it a solid two weeks every day and haven't had a single issue with it. That being said, when i leave today i am sure it wont start, but up to now the ground seems to have fixed it. Let me ask you this though, on your Suburban, have you ever had water pool in the passenger floor after a rain? Mine is SOAKED after our hard rain this weekend. Great thing about cars, their always a project...

 

this weekend I'll try to get to the starter and check it plus run that extra ground from battery to body like you did. I am pretty limited on time so it takes forever for me to make any progress. I thought that we would have run across more people that have run into this than just us, that would be too easy though. Hopefully we can make it easier for the next person.

As far as the water, I have not noticed that in mine but I will keep an eye on it and let you know. I did see a post somewhere about that but that person had not found the leak yet. If I can remember where I saw it I'll send it to you.

 

Ran the extra ground wire over the weekend. Don't drive mine often during the week so it will take a while to see if that helped. I'll let you know.

 

FYI. That didn't fix it. Started 6x then not......

next? I really hate to start replacing things without isolating this more. It is EXTREMELY inconsistant so it is very hard to pinpoint.

At least so far it has always started eventually and not left me stranded.

 

Update.

Still fighting this. Over the weekend located the nuetral safety switch. Checked/reseated the connection, wires seemed fine. Started 7x then same thing. Main things I have not tackled yet are starter and ignition. Guess that is next.

 

Imposter, I might suggest running a few more grounds too just for good measure. When you try and start it and it won't, do you hear something clicking behind the glove box? Not sure what that module actually is, but when my truck starts properly it does not click. I dont want to keep re-hashing the ground issue, i just know that is what fixed mine. When yours acts up can you tap the starter with something and get it to turn over? Usually when a starter solenoid is failing you can tap it and it will turn over. Just a suggestion. Maybe try running a dedicated ground from the battery to the BCM (under the dash driver side).

 

No, I don't get any clicking that I can tell. If you were to put yours in drive or reverse and try to start it....that is exactly how it acts. It either starts fine or does not. No dragging, clicking, or any other thing that I have noticed. You are right though, it seems like it could be an intermittant/poor connection somewhere. Just haven't had any luck finding out where yet. I appreciate all help/sugestions so please kee[p them coming. Unfortunately I have heard of at least three different solutions to this that have seemed to work from 3 different people and in all cases the symptoms were the same. The 2 simplest solutions were yours and another person that changed their battery cables. The third guy changed his starter.

So far it really hasn't been that bad because I don't drive it that much and it has always started. Plus I am becoming more familiar with the vehicle and if it turns out that I end up keeping it for any length of time then the more I know about it the better..........

 

Gentlemen,

Unfortunately I had the same thing with my 2005 Tahoe. It left me stranded twice but would jump off for some reason but the battery was hot as can be. I replaced the battery and starter in the parts house parking lot (it has 95K miles on it so I said what the h3ll) and then it would do nothing. From there I put it in the shop for the third time, and third different mechanic (first was dealership). He called me the next morning and the problem is in the ignition switch. It has nothing to do with the key etc. He tested the voltage that was being sent by the ignition switch---it sent 12v and cranked perfect for 40 or so times then it did nothing as it was only sending 5v or so. He replaced the switch ($500 or so) and it has not given me a moments trouble in a week.

So tell your mechanic to check that first instead of wasting your time. My go-to guy had mine for over a week and said he couldn't find anything---he didn't look quite like this guy did.