When I hook up my lights they won't work until I mount the trailer to the truck. Is that normal?

 

Yes unless you have ground wires hooked up on both vehicles, the tow vehicle is providing the ground for the trailer.

 

run good gage wire from the trailer to the vehicle. find a nice grounding spot for both of the ends. bolt the wire ends down. your trailer lights will light up like a christmas tree..............

 

I do have a ground on the trailer as well but maybe its not a good connection. If the trailer has a ground to the trailer frame then the lights should work when not attatched to truck right? Maybe my trailer ground is bad?

 

the vehicle and the trailer must be grounded together.........."attached"............. for your trailer to light up like a christmas tree.................each light on the trailer must also be grounded to the frame of the trailer............

run good gage wire from the trailer to the vehicle.

 

Ok so then it is normal for this? The reason I ask is my friends trailer the light will work just by plugging in the lights without being hooked up.

 

The light should come on by just plugging them in. If they don't and only come on when the trailer is attached that means your trailer wireing is not grounded and the trailer is getting it's ground through the trailer hitch. Within the trailer wireing the ground is a white wire ussually 10 gauge, trace it to where it is suppose to ground. Try to find a loose connection or even a broken wire. You don't want to leave it ungrounded the way you do because it could cause a light failure every bump you hit.

 

the vehicle and the trailer must be grounded together.........."attached"............. WHAT I MEAN BY THAT......IS............................THAT GROUND 10 GAGE WHITE WIRE "CORMACS" IS TALKING ABOUT AND ME TOO.............IT MUST HAVE A CLEAN METAL GROUNDING SURFACE AT THE TRAILER AND A CLEAN METAL GROUNDING SURFACE AT THE VEHICLE. THE TRAAILER LIGHTS SHOULD AND WILL WORK WITH THE TRAILER AND VEHICLE "UN" ATTACHED IF YOU HAVE GOOD GROUND AT BOTH ENDS WHEN YOU PLUG THE BOTH ENDS TOGETHER. IT IS INCORRECT.........NOT NORMAL....................TO ATTACH THE TRAILER AND VEHICLE TOGETHER FOR THE LIGHTS TO WORK................THOUGH IT DOES WORK.......BUT THAT IS THE WRONG WAY FOR THEM TO WORK...........THE LIGHTS TO THE TRAILER WILL FLICKER OFF AND ON IF GROUNDED THAT WAY.

 

it was a bad ground allset now Thanks