Whoa dude!
Get it away from your mechanic. He’s been milking “started car” for a week and cannot do basic starting circuit preventative maintenance?
This is a very common issue in FL. Here’s the fix I use:
1) Clean crud off battery terminals with water.
2) tighten both ends of each cable starting at the battery clamps/connectors and then the cable ends (connections to starter solenoid and ground).
3) Drive a stainless steel screw between the battery’s positive post and battery clamp on the opposite side of where the clamp gets tightened. You may need to use a small nail to make a starter hole.
If it happens again after this turn on the lights first, then start. Then repeat above steps.
Best of luck.
Clean battery terminals with a baking soda and water paste.
Thanks for the post..Been there, done that.
The mechanic has been testing all parts and manners of the circuits and sensors looking for shorts or low voltage.
BTW, he does not charge me for diagnostics, only the time/labor for the actual fix and parts. We go back 15 years plus.