I recently got a 2001 bed to put on my 2004 frame, and have the 2001 taillights that need to be hooked up to the 2004 harness. I'm unsure how to proceed and I've read through a lot of threads here trying to figure out if this has been done before, but haven't seen the same setup done before. I took a few pictures of the bulb wiring just in case it's as simple as "splice the wires this way", but was hoping someone knew enough about the differences to help. Plugging the harness from the 2001 bed into the 2004 harness end on the frame didn't work, so I'm left with figuring out where and how to do this mostly blind. Any suggestions would be appreciated. This is the last step I have before I can actually start using the truck again after nearly 10 years in the garage fixing up rust damage and replacing damaged parts, so I'd love to figure this out. Thanks in advance!

wires for the 2004 taillights that work with the truck now (but don't fit the taillight holes in the new 2001 bed)

wires for the 2001 taillights that fit the bed but don't work with the 2004 harness or truck as-is