Tail Lights different brightness?

[92 Diesel Dude]

Hellow everyone! I'm having difficulties with the rear tail light's on my 92. The right hand lights are all dimmer than the left hand tail light assembly. I have checked the bulbs and conections on both sides coming into the light housings. I assume the problem is down stream but don't know where to start. Has anyone experienced this problem?
Thanks, Diesel Dude.

[Inspector]

Check your grounds.

[jpaitala]

Grounds are number one.
Number two is to chech that your tail lights dont "collect" any moisture inside them. I have had this happen several times on other than chevy trucks... Slowly the moisture dullens the lens/makes the electrical connections bad and the lights look less brighter.

[HowieE]

With a digital voltmeter read the voltage on both sides of the bulbs while they are on. If you see any voltage on the ground side the ground has become a resistor and needs fixin.