My first mistake was I bought crappy lights. So I tossed them and I them bought new ones that are a bit more expensive and are a lot brighter (when connected directly to a battery). They work great when I first plug them in but after a few minutes they dim. I checked the voltage and it reads 7.8, when moments before it read 12.3. When I unplug one of the bulbs and plug it back in, there bright again. Any one else have this issue? I'm guessn a resistor inline with a the bulbs.... I do mean the 3rd brake light assembly. Thanks!!