Hi! I am re-wiring a '77 W-200 truck and just ran into a small problem. A circuit breaker with a small 3'-ish wire harness attached to it is located at the fuse panel. I can't find out what the other ends in this harness should be attached to. Can't find the breaker or the harness in the wiring diagram either. Pictures show the breaker, its terminals and harness. Any ideas? Thanks

I can not tell you for sure but I do believe that is for a 2 speed rear end. I know my 75 D-800 had it. That bare fuse block was used on all D & W series trucks. So maybe someone swapped it out before you got it. The one other item that comes to mind on trucks with the camper special package. It is possible that it was used for a camper harness. For now if you are not concerned about being factory original just make a diagram and remove it for now.

You are the man, Nitrousn👍😀 Exactly what I needed to know. I think I'll just tie it up under the dash😀

Hopefully that will fix you up. As I looked that harness over and the wire colors used it could of been also a harness that used a relay off that black plug. Which would of been used by the body installer on cab and chassis models for body lighting. With 10 to 16 body [marker] lights they would of needed another power source for all that draw.

Possibly for auxiliary snow plow lights?

No it was not used for plow lights that I know for sure. Plow lights were a simple switch with the hi-low inputting the push pull switch. Its either on plow or truck when you turn the main headlamp switch on.