Quote Originally Posted by mmandley View Post
I am working on adding LED run way lights to Bestia. My idea was to have yellow in the front to the just behind the fenders, then it switches to red. This way its legal on the highway and would light the trailer up and also work as evening docking lights.

I got everything done and was ready to hook it up when i discovered the voltage on my trailer is 7.5V not 12 as i would expect.

I checked at several light locations and they are all 7.5

I have all LED lights on my trailer, i checked my truck and its putting out 12.5 to the hitch harness, and then in tongue when it changes from the 7 pin harness to the trailer harness its drops to 7.5. I don't see anything that can cause this drop.

With only 7.5V my lights don't work as intended. Kinda stumped what direction to go now.
Too lazy to read all the replies, so sorry if this has been mentioned. With the trailer connected to the hitch and harness plugged up, connect your meters ground lead to the trailer and test the voltage on the truck side. If its low, you have a ground issue. If its same as before, then reverse the leads. meters ground lead on trucks chassis, then probe the trailer side and see what the voltage is. If its low, then the there is a problem in the connector.