Electrical problems on new TT?

[Grey Stray]

I'll try to make this simple.
I have an '08 Salem LA. I intend on replacing all of the exterior lighting with LED lights. I have replaced the rear brake lights(here starts the problem). The trailer was plugged into my truck but not secured via the hitch. The tail/brake lights were barely visible. These lights will blind you if it is hooked up directly to a battery. Why wouldnt they be that bright wired to the trailer. I used the common ground wire from the trailer just like the stock lights did. HELP!!!!!!!!!!!

[wvsteve]

i would say if you hook it too the truck it will get a better ground. I have a little electrical experience and when we have a floating neutral on AC your lights or whatever is attached is only getting aboout 80V enough to light it but not enough to fully light it.

[welshman599]

Hmmm, were the original lights also dim if you were hooked up exactly the same way? And did the LEDs brighten properly when the brakes were applied?

[aintgotnun]

I think I'd go with wvsteve on this one. Sounds like a weak/floating/intermittent ground. The lights and pretty much everything on your trailer are grounded to the frame. Your trucks power is grounded to the motor and frame of the truck. You are providing power from your truck to a separate vehicle and the only common ground is via a small wire through a connector that probably has some corrosion albeit minor as it does work. DC contrary to popular belief flows from negative - to positive + (yeah I know techs are taught pos + to neg -, it's easier that way) so a good ground is especially important. And since the ground on both vehicles is the largest chunks of metal, when they are only connected via a small wire it just isn't enough.