FRA1500

I have not. I've got one ready to install, but since everything tested well with the multimeter...and the bolt holding it to the back of the block is pretty stuck, I eliminated it as a likely culprit.

Thank you. Those were most of the ones I started with. I will check that further. I didn't have any looseness or issues when following the diagnosing recommendations I found for this, but could have missed something in the application of those instructions. Thus far, it does not appear to be the ignition switch. Thank you.

Only the one by the A pillar. Others haven't come up when I've been searching the last few weeks, so I was not aware of them. I'll keep searching.

My daughter bought a 2014 Silverado 1500 5.3L LT five months ago. Initially, it would not start from time to time after she had been driving, then start after sitting for a bit. We found the used car dealer had put a new battery that was too small in it. Swapped to the correct size with higher cranking amps. About a month later, it began to not start after being turned off, again. Never has there been clicking from the starter, every time there is no electrical, anywhere. We cleaned the frame ground from the battery and applied dielectric grease, checked battery ground to back of passenger side engine block, cleaned driver side frame ground and applied dielectric grease, checked ground on driver side near A pillar, checked engine block to driver side firewall ground strap, all show <.9 ohms resistance. The alternator is getting full voltage from the battery. Checked for voltage drops in the battery when the truck is turned on, then when headlights and accessories are turned on; no significant drop (<1V). Assume alternator to be good. Checked DC fuses in engine bay fuse box with multimeter, all were good. Recently, she was driving at low speed in a parking lot and the electrical and engine just shut off. After a few minutes, she was able to restart it and drove it to an auto shop. They spent an hour and a half checking it and said they can't find anything wrong. This past week, it would not start after sitting overnight. Five days later it started. I have searched the forums and youtube and am trying everything I can think of to diagnose it. What am I missing? Thanks.