Thank Tom. I asked this 'cause I put the "new" trailer cord on the trailer today, used but never on a trailer. Had a couple lights that didn't work..including the b/o brake..no vdc. Fixed all except the b/o brake..grounds, who woulda guessed?. Pulled it 10 mi, stopped at a friends, no lights at all on the trailer. I expected the worst. Checked voltage and grounds from the truck, all the way to the trailer lights. All fine. Turns out the bulbs were 12VDC!! DOH! Put some 24VDC stuff in the lights, they are fine now. As for the b/o brake, well, no brake lights on the truck ether. see "another deuce brake problem" I do a check of the lights b-4 I drive it every time, light sw. to service drive and put the ts lever to flasher and do a walk around. Guess I need soldier B to check if I have brake lights! Never thought about that.