I recently purchased my wife an 08 LT 2WD 5.3 Tahoe with 84k. We have owned it for a few months and it's acted up on us three times.

Three separate and random times the truck will not start. We will go out to drive it somewhere and there will be no interior lights, no cluster lights, nothing at all, cannot lock or unlock doors with fob, etc. Engine does not crank. Nothing happens at all. The locks on both front doors sound very "glitchy". If I disconnect the battery for 10 secs or more the truck starts fine with no hesitation. And the truck will be normal like nothing has happened for a few weeks. The first time this happened I tried to jumpstart but no luck, only after I disconnected the battery did it fire.

I have taken the battery to a parts store and had a master tech check the battery and it shows no issue and doesn't even need a charge. The battery is only 1 1/2 years old. Also, the alternator has been charging normally too (sounds like the bearing may be getting louder).

I am wondering if the body module or something else is disconnecting the battery from the car for some reason and until I disconnect battery then reconnect it resets or clears whatever is occurring.

 

I have had the same problem in my 2007 Z71. Sometimes I can hear a rapid clicking noise in the doors. There has got to be a loose connection!

 

With it being intermittent, I would not think it would be a fuse. I had a similar issue on my '98 Isuzu Trooper (also built by GM). I was completely stumped, so much so, that I took it to my mechanic that I would use for jobs that I 1) didn't want to do or 2) couldn't do.

He fixed it within an hour and cost me $70. His fix: He replaced the battery cables and installed new battery terminal connectors at the end of the new cables. He said the old cables had gotten corroded.

Corrosion could be a problem. It could even be something as simple as a loose or damaged battery connector or ground.

Check your battery connectors, your battery cables (both negative and positive).

Look for the easy things first.

 

It's the negative battery cable probably. Go to dealer with this complaint and they should know all about it. Tell them to do a voltage drop test on the negative cable. The cable will test out of spec. This causes all the concerns you are describing due to the battery having a poor ground connection makes it seem like there isn't even a battery in the vehicle. I'm pretty confident this is your problem. Do quite a few of them but all vehicles can be different but I'm confident in the way you describe it.

 

I have suspected the battery cable on the negative post. Even when I tighten the crap out of it, it still seems like it hadn't gripped the post. Thanks!