i've got three mysterious wires coming from under the truck that run up into the engine compartment and then goes through the fire wall. i just got the truck and it's my tow rig. i saw that it's also wired up for trailer breaks and i was wondering if maybe those three wires might be for a tack that the previous owner might have just cut out.
so... is there any way that i might be able to test the wires to see if my hunch was true?

thanks,
-Bryan