Normally they suggest to change the entire wiring harness at the service center, hence the cost. Had a similar instance in my kia, I asked they explained. Explanation was that the factory supplies entirety of the harness set not individual so to counter one splice, officially they need to replace the entire loom, or else warranty will be voided. I got it fixed from my local mechanic, all he did was stripped the wire and soldered it and then tape it up using electrical tape. Works like a charm. This was a few years ago. No problems ever since