Wiring question

[esox07]

Long story short, I installed a votage meter/usb panel in my trailer yesterday. I forgot to disconnect the batttery. Anyway, when I got done with the wiring, I tested it and got nothing. I tested the trailer lights which is what I patched into and some of the lights (LED's) came on and some didn't. But the ones that came on were very low brightness. I couldn't figure it out. If none came on at all, I would have guessed it was a fuse, but since some came on low, I figured it was still getting power. Finally, I checked and sure enough, it was a fuse. After I changed it, all was good.
My question is: Why did some of the LED lights come on partially if the fuse was blown? It was the same with out the fuse at all?

[hondapro]

Sounds like you are getting a back feed problem thru one of the wires you spliced into.

[enblethen]

What voltage is the voltage/USB panel?
120 volt AC or 12 volts DC?

[GrandpaKip]

The fact that you get juice to the lights when the fuse is out is a sign of miswiring. Somehow you have bypassed the fuse.
Did you come off an adjacent light or the fuse box?
Have you taken the fuse out again and still have some light?
If so, that isn’t right.
I would definitely go back and check what you did. Take it apart and do it again.
Good luck.

[Bobbo]

I don't know, but wonder if there was enough inductive voltage from the 120v hot to ground to produce that.