Short to power in the brake light circuit. Most likely, the fault is in the switch itself.
I have no running lights on my 2006 Peterbilt 387 all of the lights work
There is plug on air line marked drl next to fuse box
Maby short in harness along rocker panels or on trunk......take trim loose turn on dash and tail lights and start jiggling harness wires. Moisture can cause problems like this as well.....
I found it easier to use the wires to the tail lights on the tractor.
just about anywhere as long as you have the proper safety signs and lights
Check headlights and dashboard lights first. If no/minimal power for the lights then replace battery.
Your leaking at your clearance lights. You will have to take out your storage compartments above your windshield and use silicone caulk around the inside screws for the lights and then you will have to also caulk around the lights and the screw holes on the outside around the clearance lights.
Yes.
That depends on what brake lights you have. If you have the squared ones with the reverse lights built in, those covers are held in with screws. If you have the Truck Lite sealed lights, you don't take those off - you replace the entire unit.
Stuck brake light switch, or a short to power somewhere in the brake light circuit.
Fuses?
There's continuous power supplied to the circuit. When the switch contacts, it closes the circuit and allows the power to go to the brake lights.