Here are the rear lighting wire colors:

Lt grn / orn = Left turn and stop
Orn / lt blu = Right turn and stop
Brn = Tail, license, running
Blk/pnk = Back up
Black (slightly larger than the ones above) = Ground for rear lighting harness.
Lt grn = High mount brake light. Not used. May not be present in a later 2000 harness.

 

At the rear of the left frame, there should be two connectors coming out of the main harness that runs forward.
One has 6 fairly small gauge wires in it. This connector is for the bed lighting.
The other has 7 wires in it, 3 of them are large-ish gauge wires. This connector is for the 7-pin trailer tow connector.

Are there any connectors on the harness in the truck? Is the connector still on the bed wiring?
If = yes to either question, I would attempt to source a mating connector and splice it to the wires. Preferably, the bed wiring still has its connector, source a mating connector and splice it to the truck.

If all you have at the rear of the truck is a bunch of wires hanging out with no connectors:

Compare the colors in the bed harness to the truck harness. If you find the same wire in each harness, connect them together. You can use a flat-5 trailer wiring connector so you can remove the bed in the future without cutting wires. These should be available at a parts house. Splice the connector to both the truck and the bed harnesses.

Here are the bed lighting colors:

Lt grn / orn = Left turn and stop
Orn / lt blu = Right turn and stop
Brn = Tail, license, running
Blk/pnk = Back up
Black (slightly larger than the ones above) = Ground for rear lighting harness.
Lt grn = High mount brake light. Not used. May not be present in a later 2000 harness.

The rest of the wires at the rear of the truck are the Trailer Tow connector. I can help you with those also, if you need it.

Thanks, let me start by saying I really appreciate the help. I've been searching the internet for days for wiring diagrams and what not but this is the most helpful thing yet.

There are no connectors coming out of my bed, just the two sets of wires for their respective uses but each tied off. But, I do have the connector on the bed, so should I look into getting a matching connector for the tail light wires on my truck, connect them to their respective colors, and I should be good, right?

 

OP registered, got what he needed, and is gone........ SOS

 

OP didn't need this.

 

i have a complete 2002 wiring diagram book, freekin 600 pages or something

that shows connectors:
1) C422 - right side
-- pin 1 black/pink - reverse lights
-- pin 2 black - ground
-- pin 3 brown - license and park light
-- pin 4 orange/lt blue - right turn / brake / hazard

2) C432 - left side
-- pin 1 - black/pink - reverse
-- pin 2 - black - ground
-- pin 3 - brown - license and park
-- pin 4 - lt green / orange - left turn / brake / hazard

reverse lamps are on a separate connector C487 (left), C488 (right).

grrr, this gets complicated. looks like there's different harnesses for the different versions. connector C408 is common to both SRW and no-bed and I suspect is up near the cab, but just has the left/right turn/brake/hazard lamp on it..

of course, these connectors aren't shown in the connector diagrams, nor is their location indicated anywhere I stumbled on.

 

I just bought an F350 with a F250 swapped bed. All the lights were working besides my taillights. It was VERY frustrating. It turned out the taillight wire corroded so much it just disintegrated in one part near the hitch. The Haynes manual provided very good schematic diagrams without being overly detailed. I can confirm the above colors, but you will probably want to get a Hayne's manual so you can confirm your year and so forth (and they're just a handy reference). Good luck!!

 

oh, that C422/C423 was specifically for 'no bed' trucks (flatbeds, utility, etc). pickup bed trucks have a different harness from C408 to C????, that was where I was going when I started to lose track of all the connectors, spread across 8 different pages in a 600 page book.