Harness replacement (being screwed by dealer advice)

Hi all,

Have had a nightmare trying to get our 06 Prius repaired. The issue started when the triangle of death appeared and the car wouldn't turn on.

Step 1 - Took it to a mechanic. They replaced the ABS relays that were fried, thinking that was the issue. Then they did further tests and told us that hybrid battery needed to be replaced. They quoted us a lot to replace the battery.

Step 2 - found a prius battery specialist that would replace the battery for much cheaper. Took it here and they then said that there was in issue with the communication between the battery and the ECU, and that we should take it to a dealer to get checked out.

Step 3 - Take it (begrudgingly) to a Toyota dealer. They seem to think the ABS relays were fried AGAIN, and mention they have some spares lying around that they put in. They then told us there was water damage that fried the AC amplifier and the ECU and the SRS, and that these all needed to be replaced. That was last week. Called today, and they are now saying that there is a shorted electrical harness, and that the entire harness needs replacing, at a cost of $5,800 for the harness, (in addition to the $1,700 for the ECU, SRS and AC Amp).

Left feeling like we are getting royally bent over, as I expected would happen taking the car to a dealer. At this point I'm really not even sure what the root cause is, but it sounds extreme that the entire harness needs replacing.

I'm going to go to the dealer in person and ask to see the print out of the reports they have run and to show me what the issue is with the harness.

That being said, not sure what the next play is here. Do I try take it to a local mechanic and get a second opinion? The $7000 the dealership is asking is more than we paid for the car in the first place and seems ludicrously expensive.

Any advice would be greatly appreciated (in before "why did you take it to a dealer in the first place you f**ing tool").

TL;DR car broke, now at dealer and being asked for a lot of $$ when I'm not convinced the repairs are actually required.