Did you wire the extra taillight with it's own circuit or pigtail it off of the left taillight? A RH taillight was an option and the factory harness came with a seperate circuit to the RH light. As noted above a good ground is required along with a dedicated circuit (one wire from the HL switch to the TL & one wire from the BL switch to the BL) to the new light. I echo the sentiments above that you have a great looking truck!
I might also add that your single filiment bulbs are pretty dim anyway. you can get 6V LEDs here:
http://www.highspeedmotors.com/Webled.html that should be much brighter. I'm going to order some next week. The problem is they are $28 per bulb so it's over $100 for both taillights & both brakelights.
