Can a Fuse box go bad? 66 Mustang

[sdmustangrider]

Well if some of you kept up with my electrical issues, I've been in the s*** can trying to get it solved. Today, I think I found the bad grounding. When I test the courtesy light at the door jamb with a test light, it lights up. When the fuse is taken out, the light is gone and I was told on another forum that means the bad grounding is somewhere in the wiring of the courtesy lights, cigarette lighter I believe, and something else. Headlights? I'm wondering if it's possible the fuse box can be bad. I rechecked all my wiring for the courtesy lights and nothing is loose at all or rubbing open wire to metal.

[Huskinhano]

Sorry I'm not familiar with your electrical problems. Yes, fuse blocks can go bad. The wiring in these cars or any other car for that matter back then, electrical loads were light and so was the wiring. Today we add devices that use a lot of power. With the extra amperage going through small gauge wire creates heat which cause problems.

Now what you describe of your courtesy light, it sounds like it is working correctly. There is no grounding in the wiring harness or fuse block. Each light, ect has it's own ground typically. Get yourself a cheap digital volt meter. To measure voltage you need to read across the light or what ever to get the volt reading. If you put one lead to the metal ground and the other to the end of a wire, you will always, always read the voltage of the battery no matter how much resistance the wire has. If you want to read how much voltage is lost on the wiring, put one lead at the + term on the batt and the other lead to the other end, such as a + side of a light, not the metal ground. Now you will measure how much voltage is lost on the wiring.

[sdmustangrider]

Sorry. I'm a little confused what you said. I'm using a test light which is needed as well as a volt meter I'm using too.