Sept PO300, April 2022, P1404, April 26 PO302 and c121c

Okay, I hope it goes ok for you. I know it's difficult when vehicles break down. Unfortunately, they all do at some point.

It's unfortunate that the other shop broke a bolt off in the engine block. That can end up being a lot of work. So hopefully after this, everything will be taken care of.

Okay, I can see the water pump bolts onto the Timing Chain Cover. The water pump is probably leaking because of the missing bolt. I'm not sure why he can't drill out the broken bolt and re-tap the whole with new threads and get a little bigger bolt to put in there. That's what I would do. $700.00 is a lot for a timing cover, all due to one broken bolt? That's going to be $2,000.00 for a water pump. What were they going to do for the $1,300.00?

C102 is a 10-pin connector and what they call thermal damage is a melted connector. It looks like they intend on replacing the entire engine wiring harness because they probably can't find the high resistance area that caused the connector to melt. The dealership is not going to give you a payment plan like you mentioned earlier. The price will be the same or higher because labor at dealerships is usually higher. Most likely a bad Ground or Power feed is causing the heat that melted the connector.
The Totally Integrated Power Module which is usually on the driver side in the engine compartment powers almost everything in this vehicle. It would help if you checked the back of all the Fuse panels in the vehicle for any water intrusion. Including the Fuse panels inside the vehicle as well.

One thing you can tell the mechanic to do, is if there was a melted connector, they should use a thermal camera to look for hot spots in the vehicle. It is a very effective way to find other bad connectors/ connections that would cause an ECM connector to melt. It is a new way of diagnosing issues like this. It will speed up the whole process.

The component near the driver side tire I think you're meaning, that is the Totally Integrated Power Module, Its basically the Body Control Module, but it powers up everything. And they have a lot of problems and always have. They are on a Network with the Engine Control Module.

Just to give you an idea of the Computer network in your vehicle. Pages 1 and 2 is the Totally Integrated Power Module (TIPM) and the Engine (Powertrain Control Module). Every Blue box on pages 1 to 4 is an Electronic Control Module in the Vehicle. Page 5 shows you more in depth what the TIPM does. If you notice on the top right is the Powertrain Control Module. Those 2 (in yellow) wires are the Network wires that run into the TIPM. From there all the other modules in the vehicle are connected to it. So, if there is a problem with the TIPM, all the data has to go through it to get to the Powertrain Control Module (ECM). It's very complex.

The ECM is near the TIPM, they are both on the driver side engine compartment,
So, if they are looking for a heat issue, using a thermal camera is a great method of finding hot spots that they wouldn't normally be able to see. Since there are so many different modules and things that can go wrong, that's probably why they just want to replace the wiring harness. They probably think it will be faster than trying to find the actual problem. It could be a loose connector anywhere causing heat issues.
But when they say a thermal event, that is caused by high resistance causing a heat buildup and that's how connectors melt.

This is why it's so difficult sometimes to find problems in newer vehicles. They are built too complex.