**Electrical Diagnoses can be very difficult and some times easy.  The issues are always 1 of 4 things (Open Circuit)(Too High Of Resistance) (Short To Ground) (Device needs to be replaced)

**I have a portable switch that allow me to operate window motors, horns, light bulbs etc. allowing me to test the device itself to see if its broken or the circuit has issues. As long as I can Access the devices connection.

**I am able to trace wires using special equipment, as you know there are so many different wiring harnesses in RV's  

**I am also able to find breaks in wires with minimum damage to wiring harnesses

** I can test Relays and manually operate them

**I am able to wire 120v AC outlets and switches