Shop holding my truck hostage for 4 months, not for non payment?

Is there a law on a mechanic shop holding your truck hostage?? I had another motor put in my truck and the mechanic keeps saying he's waiting on a specific person to do the wiring harness so I will be compatible to that Motor. He initially told me it should only take a month and a half to do it and now it's been 4 months going on 5. The motor swap has been done by truck not running supposedly because of the harness. Isn't that a Civil lawsuit due to loss wages, etc?

 

That's what I plan on doing as well but I may need to take another mechanic with me make sure I'm paying them for what they already done and to make sure nothing else is missing off the truck.. I've asked him several times about how much I'm looking at to pay already and he keeps saying he would have to wait until the harness is done to get a accurate number

 

Why would charge me double? Every week I go to him and ask him when will the truck be finish, he says it will be ready the next week. That has been for the last 3.5 months

 

Negative. He said he's waiting on his guy that actually does the harness stuff to travel to the shop from Texas to do it. Other the harness, he says the truck is done. I told him about a guy that can do the job that's closer but he exist on his guy doing it, then he said he will get a guy from Florida to do it. He keeps changing his story so it makes me feel that he lying about something.

 

Went to a 60 series Detroit