Need help with trailer back up lights

[integrityman]

I really want to put some back up lights on my trailer. I have a 7 pole plug on my truck. It is my understanding that the "auxiliary" is commonly used for back up lights. Is this true? Would back up lights only come on when the truck is put in reverse? Or is this something that I need to hard wire into the back up lights from the truck?

HELP!!!!

(yea, I backed into something!- mailbox if your curious)

[unkownfl]

There should be atleast one empty terminal on the plug people use it to charge the battery for brakes or lights. How many watt bulbs are you using. Divide the watts by the voltage and you get amps. See how many amps the wires are drawing and check the fuse on the circuit. You need to calculate the load of the wire by its size and length unless you want to get into physics. If you want a spot light you are going to be over. So wire a new line to the battery use a protective source (fuse) and a toggle switch wire it through the plug then wire it to the lights.