Tail light problem, 2002 2720

Got a problem with the tail lights on my 2720 (2002), and I wonder of anyone has had the same dilema.  Ok, here goes...

When my truck headlights are off, "stop", "directional", "hazard", and "back up lights" all work properly.

However...when the truck parking or headlights are turned on, the tail lights go completely dead. Only the perimeter running lights operate.

We had extensive torsion bar work performed at the dealer this winter (unit dis-assembled and re-assembled), and I wonder of thats the root of the problem...

Thanks for any input

I found the problem with the help of my trusty wiring guy. The tail lights have sustained significant corrosion due to water entering the light fixture from above, which corroded the ground screw on the lower bulb of the fixture (right where all the water drains from the roof of the camper). I plan to use a soft putty of some sort to bed / seal the top and sides of the fixture, and drill small holes so that what does leak in can drip out.

It is really a poorly made fixture...do the new models have a more substantial fixture?

Cindy and John, and Other folks.

I recommend you place some grease, yes grease on the
end of the buld that goes into the bulb socket. This will prevent the bulb contacts from becoming corroded.

I use 'White Grease' it is also callled 'Brake Grease'. Dip the end of the bulb into the grease, wipe off the excess, but leave all of the bulb contacts coated.  

Should be used on any bulbs exposed to moisture.

Pleased you found your problem.

DR. John