Model: Z51 LT3

After trying to install a battery tender (the same way I have on my past three cars) rather than using the one that came with the car (strictly personal preference), the car suddenly lost power.

With two days of experimentation, I found that by tightening two of the bolts on the battery to just the right amount, power was restored to the car. I found that for some reason, by tapping the conductive plate beneath these two bolts, power would come back, only to shut off again a few ignitions later.

Well, this morning I truly thought I had it fixed. The plate seemed to be positioned the way it should, the bolts were tightened, and the electrical system was working. Doors would open, lights would come on, the car would start.

However, after pulling it into our turn-around in our driveway, I tried to turn it on again to access some features in the Vehicle menu. As soon as pressed Engine Start, there was a click and the car went dead again. No electricity whatsoever and clearly no start-up.

After opening up the battery compartment (for the twentieth time), the power was suddenly restored again? This time without touching any bolts or plates or anything.

Since I got it going, I took it out to the service station where I will have to wait until Monday (or later) for it to be worked on since the technician doesn't work on the weekends.

Any ideas as to what this was? It makes no sense.

Side note: We did try jump starting, it did not work at all.
Side note #2: We charged it with the battery charger that came with the car during one of the times the electrical system was working. Even with it saying it was fully charged, the car would sometimes shut off completely when trying to turn it on.

 

To me it sounds like the battery cable where it attaches to the fuse box in the back may be loose or the ground line. Or it could be a bad battery with a poor connection or intermittent terminal connection inside of it. What ever it is, I suspect this should be a very easy issue to fix as I'm sure it's something that originates in the trunk area and given that there is only a positive and negative to deal with, finding the root cause should be simple. What I would of done was get a second set of hands there so one person could hit the start button when the car is unable to be started and the other can wiggle the power and ground cable to determine which one it is. I'd bet that wiggling the cable would get a result that would at least shed some light on which line is the root cause. From there, I'd follow that line and see if it's something on the other end that is loose. Then I'd try to find a second battery to test with assuming you haven't already found the issue.

 

Possibly a bad battery .... internal short.

as recommended ... try another

 

Sounds like a poor connection somewhere other than the battery terminals.

When you try to start it the loose connection was enough top power on your electronics but as soon as you try to pull any amps through that loose connection it loses it.

Sounds like you popping the trunk moved it enough to make contact.

Good luck! Hopefully it's a simple fix.