[AT] What is a Relay?

[Ricky Prescott]

How does a Relay switch work?  My lights on my truck went out.  It burned up the plug that goes into the switch.  I rewired it. My Mechanic said I need to install a relay so when I hook up my trailer lights it won't burn up the plug again.  I am wondering what I need.  The wiring in the  old dodge is not heavy enough to handle all the amps the trailer lights draw.  I hope I made this clear.  Thanks, Ricky