1993 D250. Right headlight is dim. On high beams even more pronounced. Daylight running lights are not running (truck is in Canada). Inside cab, right turn signal indication is partly illuminated, but not flashing. Otherwise signals work when called upon. Expect something pooched with daylight running lights relay...Uhm, where might I find that?

 

Check the ground on your right light.

 

As mentioned...grounds are often over looked and are essential. Find, clean (sand to bare metal) and install...if you can add a dab of dielectric grease it will help the connection last longer before any corrosion can get past to foul things up.

Daytime running light relay is on the pass side inner fender kind of in front of and below the washer fluid reservoir.

 

Nope. Just a dim headlight and one of the two filaments was burnt out....and a dim operator.