Wow in all honesty I think they're taking you for a ride
since it's already out of warranty.
I would've found an Auto Electrical reputable shop, And had them diagnose it, And had them fix it.
Damn dealers going to keep you going in circles with what is the problem to keep changing parts, And costing you money, And possibly NOT resolving anything.
Remember this is where they make money on out of warranty work.
Thats part of the business
Im very pissed to hear the dealer can't be honest you, And just eat the misdiagnosed parts since it's NOT your fault, and only charge you for what will fix it.
This is just my opinion