do all black wires go to ground?

use a meter see if it has voltage from wire to ground,
if not switch to continuity, and see if reads a short to ground

I would never assume what the function of a wire is based on it's color. That's just asking for trouble.

I just discovered this myself. If you have black and white wires to interior fixtures, the white is ground, and black is positive.

If you have black and red wires to the fixtures, the black is ground and the red is positive.

However, in both cases the battery cables are black to ground and red to positive.

Are we all confused now?

Of course, you should always check with a meter to confirm.

Take picture(s) of the wires and area. Send them to the service provider and request info.

As far as I know, and I am not an expert, most if not all vehicles are made with a single wiring harness regardless of options because wire is cheaper than having multiple harnesses. This means that unless yours has every option ever offered, there are going to be wires that go nowhere and connectors that are unused hanging out various places. So unless something stopped working, it is unlikely there is anything wrong.

thanks guys, travelin has a good idea ,I should have though of that. gettin old I guess , and I won,t just tinker with them , I could really make things a lot worse.

I would find a phone number and at least call the service guy.

:) Hi, as a Ford, Lincoln, and Mercury mechanic the black wires were ground wires. But the German made Mercury Capri used brown wires for grounding. (this was in the 70's ) Also the Capri had several un-used wire connectors for accessories that these vehicles didn't have. I had several customers who decided that these un-used connectors needed to be connected and caused all kinds of problems.


Ask the shop or leave these wires alone.

Use a multimeter and check for continuity between that spade connector and the battery negative post. that will tell you if it is a ground wire but where it plugs in to is still a question. It could be a ground wire for an optional piece of equipment that you don't have and the wire just got repositioned out where you can see it during the battery swap.

I would but its 300 miles back and the wife and daughter had this done at a fair grounds ,road service did the work. guess it,ll give me a project to figure out.