Did you make sure the grounds are clean? That's what it sounds like to me...a bad ground. Is there dirt or anything like that where the lights are grounded?

I also just got a set of tail lights where the ground was actually a white wire and the black (should be the ground color) was the tail lamp wire... but then I don't see why, in that case they would have worked in the first place.

Gun it and run it!
1981 CJ5,258,T-176,D300,AMC 20,Dana 30,Trxus M/T 31x10.50, Rancho 5000's, GroundPounderFab front bumper, polyethylene gas tank, aluminum dash, AutoMeter gauges

What this country needs is unemployed politicians.