Try plugging it up without the trailer on the truck ball and see what happens. If it gets worse or they don't work at all then you know it's a ground issue.

.02

Check the plug on your truck for power. Make sure that the problem is not with the truck. I have had the same type of setup on my Z71 for one year and granted we go through winter up here the but the wires had broken off. If you have power from your truck, then I agree that it is either a bad ground or possibly a 2 - stage bulb that is burned out.

Check your ball for excessive rust, some trialers ground out thru them. Also if you have replaced any lights make sure the grounds and on metal not just paint itself. If it is a 6 way or 7 way plug take the set screws off and check to see if any of the wires in the plug end came loose. If your truck dosent have a ground going thru the plug add one there to match the trailer plug. If you have to strip all the wiring its not that bad, you can buy the whole harness from any trailer shop or do the light kits from wallmart and leave the lights out of it.

sounds like a bad ground to me

Just stop and isolate the problem to truck or trailer.
Test the truck signal first with a volt meter. Make sure you're getting the juce when you should be.

Than look at the trailer. But it's probably the trailer lights.

I just threw out the standard lights from my trailer and put on a nice set of LED lights... MUCH better.

I got sick of worrying about grounds on all of the different trailers I pull so I just ran a three foot ground wire from the tounge of all of them, including goosenecks, and a four inch stub wire on the hitch. I might sound dumb but I have not had a problem with a ground since.

I checked the bulbs, that was my first thought, though I thought blowing both bulbs at the exact same time was a little odd. Bulbs are okay. My trailer does not grounds through the trailer hitch, it grounds through the plugs. What I don't get is why is the ground good enough for the side lamps and tail lights to work, but not the brake light filiments. When I turn the lights on, the lights on the trailer seem "brighter' than normal. Or maybe I'm just losing my mind, I don't know. Good idea about checking where the Dodge plug plugs into for power, then checking the "out" side of the Dodge plug for power (where the trailer plug plugs into). Thanks guy. It's comforting to know help is just a keyboard away.

sounds like the blinker fluid.. or the exhaust belt

Damn, forgot about that blinker fluid.

LOL

i think it's a ground wire.. mine.. I'd push on the brakes and it would cut the radio out int he truck..