Reviving this thread... i'm having a similar problem: hovering at 11.something Volts on my brake lights and turn signals. It seems this cheepo-hopkins trailer light converter is not handling it very well. When the headlights are off, brake/turn signal lights work fine (11.8V), but with the head/tail lights on - it seems the voltage drops just enough to be under the threshold of the converter! apparently 11.3V is too low! The result is that the brakes and flashers don't work at night. arrrg

I'm thinking the Atlantic British converter should do the trick, from what Livingintheskies is saying the result is low voltage at the trailer lights - but at least it's getting there! is this right? Anybody has had similar experiences?

 

What's your voltage at the battery? Is your device grounded well? I'd just run a separate power wire from your accessories circuit and call it good.

 

Maybe that's the problem, it's not self powered... I figured it would work since the original one and the Atlantic British ones aren't powered...
The battery is over 12V and i also tried with a charger connected while testing. I'll recheck the ground to make sure (do you know where the ground on the plug terminates? I'm talking about the plug floating when you remove the RR tail light).
I was blaming the 1ohm resistor in line with the turn signals and figured it might not get any better... But if you guys get a solid 12v with headlights on I guess I'll have to track down the issue... :/

 

Couldn't tell you I'm afraid. My trailer wiring situation is... Well, let's just say some idiot high schooler (my prior self) did it for me and I've yet to fix it.

Anyway...

 

 

Update: it never occurred to me that the hopkins trailer light TESTER might be the thing that is just not right.
Curse those little blinking lights!

I put my voltmeter to the plug and the signal is going through. 11.3V is good enough for me. Hopefully the Uhaul guys agrees.