I've recently decided to convert all exterior lighting besides headlights to LED. I Used a great duty flasher relay to eliminate hyperblink. After trying resistors originally which had varied results. Now with the rear brake lights working, and turn signals working correctly, the problem now is with rear parking lights. They simply don't work. After taking resistors out everything is wired original. I've even tried switching polarity with no luck. With a test light it shows no current, and I've checked fuse. Any ideas????

 

Make sure you have a good ground for the black wire at the tail lamp socket.
Are the front parking lamps working? If yes, the fuse and switch are OK.
License plate lamp working? If yes, you have power available for the rear parking lamps. Look for connector, grounding, or wire harness issues.