Hot wire?

That doesn't sound right. Your old lights would require more current than the LED lights. The advantage of LED lights is that they provide more light with less current requirements.

What is the .11-.12? What are you measuring, and where?

edit: Try this: disconnect your old lights, and connect the new LED lights where the old lights were connected. It seems like you're trying to connect both of them at the same time?

 

You may need to run them in a series wiring pattern, I assume you tried parallel and they wont light up.

 

While back I was changing out the incandescent lights for led's in a bullrack. Started at the back Pulled the first incandescent (which was working ) put in a bench tested led and I got nothing, no light. Okay after a little cussing and scratching my head I decided to start at the front of the trailer and the led worked. Worked my way back and every led worked including the one I started with. Moral of the story (I think) led's require less amps but are sensitive to voltage, at least that was my theory

 

I'll bet thats his problem.
Drawing more amps then it is set up for.

 

Its worth a test.

 

That make sinces because with out the ground nothing works

 

There is another test to consider, check the ohms of the circuitry, If the LED are sensitive to resistance, ie measured in ohms, they may not function at all. The regular light create resistance by heating a wire enough to make it white hot. light emitting diodes are mini transistors that need a certain power supply rated in watts. Watts are equal to RMS, root mean squared. Voltage divided By resistance squared equals power measures in watts. This is why I see you get conductivity when going direct off the battery, or without the incandescent lamps hooked up.

Is there specification listed on the instruction as to what power is required other than voltage?

 

What year is your truck

That can't be right eather.
Because if Leds work off less amp then the blob?
It wouldn't be the wire