The right rear directional doesn't work and I get this erratic sound when trying to use it. The 3rd brake light also doesn't work?
What really blows is this just started happening yesterday and the truck is overdue for it's inspection sticker.

Any ideas?

 

What is the "erratic sound"? If there is one or both (back and/or front) lights that are out, the flasher will operate at a faster rate, which identifies that problem. As for the 3rd brake light, is it safe to assume that the bulb is good?

 

The erratic is the flasher operating at a faster rate.
Only light that is not working is the back right side directional..........that and the 3rd brake light.
The buld in the 3rd Brake light looks to be fine.

Thanks

 

Try changing the bulbs and check the ground wires when you have the covers off.