That's really odd. Do they all just have the small pigtail harness coming out of the back? No resistor or anything?

 

Yes.

 

The other issue is the plug for the led turn signals plugs into the old light socket and looks like the bottom of the old turn signal bulb as opposed to a actual plug in type connector at the wiring junction. I plugged mine in and when they didn-lt work I unplugged them and the cheap wires they used that fold over the bottom of the plug on part bent and broke off making them.useless

 

Mine did the same thing. I even reconfigured the wires, didn't help. They still work right when I bench them, just not in the truck.