I'm adding a few accessories to my 99 F-350 4x4 and I keep finding all kinds of plugs in the dash that are not attached to anything. Like the round black plug in the picture. It has a black wire, a red wire with a yellow stripe, pick wire with a blue stripe, tan wire with a orange stripe. Coming out of the same loom is a light blue wire with a white stripe but its not hooked to the plug and it has a piece if shrink wrap on the end of it.

 

Thats for the PTO equiped trucks.

 

Yep, as stated it for PTO functions. I have a Auxillary Idle Control Module and that's where it plugs in to power the unit. From there I can control idle speed, put truck in high idle and such.

 

That's also a quick source for key on power of you are wiring accessories.

 

Cool, Thanks!!! That answers what the round black plug is for but like I said, I found several. The black plug on top is plugged into the back of the dash to the left of the 12-volt power port. The grey plug on the bottom was plugged into the back of the dash to the left of the heater control panel.
What are they for?
I haven't checked to see if any of the wires have 12-volts but if they have 12-volts I would assume that they have a fuse in the fuse box. Or there should be a place to put a fuse in the fuse box to energize the 12-volt wire in the plug. How do I determine which fuse is for those plugs?

 

Those are for the trucks equiped with trailer brake controls

 

The two plugs in your second picture are for different things. The black one goes to the airbag switch, which if equipped is right next, to the left, of your 12v power port. The grey one goes to the electronic 4wd switch if the truck is equipped with ESOF. I would imagine your truck has neither of those so they are just dead ended into the plastic dash panel.

Baatzy

 

Miss that one, discard my last post.

 

Here is your chance to redeem yourself z31freakify. Firefighter 1406 said "That's also a quick source for key on power of you are wiring accessories". Which fuses in my fuse box are for the 12-volt wire in those plugs?