Disconnecting the battery is a good practice, but most of the time, if you are actually testing circuits to find the correct one to connect to, you need the battery connected to do so. And whenever you test any wiring in cars, you really shouldn't use a test light. When you are using a test light, you are pulling a good amount of current (relatively speaking) through that wire. Use a Digital Multi Meter to prevent damage to components in the vehicle. Now if you are working on a car from the 60's with no computers, etc. then using a test light will not have as much of a chance of damaging circuits, but a DMM will work just as well, and pose no risk.
Good to see that they did not charge you. If I remember correctly tho, the ipod adapter you instaled requires no wiring besides just plugging it in, am I correct? They just fed you some bull ish about shorting out a wire, cuz that was the easiest thing to say. If you "short" a wire, you are basically grounding it (in an automotive application), and completing the circuit back to the battery. Depending on the circuit this would either damage a component, blow a fuse, or melt the wire. I get quite a few customers who come from the dealer saying that they shorted something out, when in fact that is not the case. It is mostly because the guys at a dealer don't know much about wiring, and the terminology, so they say whatever sounds right to the customer. Had a wire for the airbag system actually been shorted, they would have had to replace the entire harness, since you are not supposed to 'repair' airbag wiring. If they 'fixed' an airbag wire that was shorted, and you got into an accident where the airbag did not deploy, etc. they would be in trouble.
I am not saying that they did not fix the problem properly, just that they wanted you to feel like you did not know what you were doing, and they did. That way if you want something done later, you will pay them. As far as them 'knowing' you just put the ipod thing in, dealers will blame ANYTHING AND EVERYTHING aftermarket. I have a couple of friends who are mechanics for dealers, and I hear the stories about how they did not want to get paid warranty rate to fix a problem, so they blame it on the radio/alarm/remote start that was installed! Also, to help prove my point that most mechanics know very little about the electrical aspect, who do you think installed the stereo systems, alarms and remote starts in their cars?
Again, not saying they did not fix it right, just take whatever a dealer tells you with a grain of salt.
