Old topic but need advice

Do your installs the right way.  They will eventually adjust.  In the long run you'll save the shop time, money and headaches.  In my line of work, I work smart, efficient and by the book.  I have high customer satisfaction and few callbacks.  And I'm respected.  The other guys who take the shortcuts and don't pay attention to the details are stuck with the complaints and cancelations.

If you don't respect your work you won't enjoy it.

Something to consider here is simple. The integrity of the connection. If they are not soldering their connections as you have described above, then that connection will ultimately fail, the same with the tape that is above it. Now in the days before a harness, we had to cut, solder and heatshrink ideally. The best connection however to save install time, maintain the integrity of the harness and be safe overall, is to use a harness and either solder / heatshrink the connection or use a butt connector. There is nothing wrong with their method, provided they add solder and heatshrink ideally (kinda next to impossible on a splice type connection though so tape will have to suffice.)

Do it the right way. Just because they hack doesn't mean you need to. If they give you a hard time, leave. I am sure there are other, better shops that will have the patience for jobs well done, and ones that don't come back with problems.

Developing good habits early in this industry will set you apart from the hacks and pros, that simple. You are right, they are idiots for not using the idiot or dummy plugs. Hell, i"ve used idiot plugs on ferrari's!

You can either use properly installed crimp connections or solder. Soldering is nice but you want to look at how all of the other connections are made in the car originally. Very few if any are soldered. Most factory wires are terminated with crimp connections. It would be nice if all of the factory connections were soldered but they aren't. You can make yours last a lot longer if you want to.

Years ago there were no harness adaptors out there and the only reason today not to use one is if there is not one made HOWEVER there's no reason you couldn't make one. I've made my fair share of harness adaptors through the years as the aftermarket does not cover everything 100% or it's cost prohibitive to have one made and what I've done is look at the plug and see if another harness can have the pins and wires pulled out of it to essentially make my own plug but without the main plastic connector to hold it all together as one. I've also soldered wire directly onto pin ends in a factory harness and slid shrink tubing over each individual one to prevent shorts. Using harness adaptors is always a good thing but there is always going to be some vehicle out there that you may have to go back onto the wire, strip the insulation back, wrap the wires together, solder it, wrap it with tape, and then add a wire tie or two to keep the tape from unraveling but this is only if you have some really old vehicle. What you never want to do is cut off a factory end.

Jim