Lighting issue. Need help

Carolyn

When the lights on the tow vehicle are “on” or on “automatic” we have no lights on the trailer. With lights off everything works perfectly. We have replaced the 7 way plug. Any ideas?

Carolyn

also, we checked the tow vehicle with another trailer and all work perfectly.

Bayliss

@Carolyn, is this issue occurring whether the tow vehicle ignition is turned "on" or "off?"  I am wondering if it has something to do with the isolation relay on your tow vehicle (which cuts the tow vehicle power to the trailer when the tow vehicle ignition is off), assuming yours has that relay (not all tow vehicles have it.)

AirBoss

Can you clarify? When you say "With lights off everything works perfectly", what is working perfectly? Brake lights and turn signals only.  

With the TV off entirely, what happens when you engage the 4-way flashers...and with the TV running with light switch in "Auto" or "On?" Are you using a wireless trailer brake system like a Prodigy where the T@B's 7-pin plugs into the braking system module, then the module is plugged into the TV? I ask because you also said when you switch trailers all lights work as they're supposed to, correct? That would seem to indicate an issue with your T@B, not the TV.

Troubleshooting electrical can be mind-numbing. And there are some VERY smart folks on here who know a lot more than I do about this sort of thing. No doubt they'll offer up some really good advice! 

Denny16

The trailer lights are not going to be on when the TV lights are in Auto and the sun is shinning.  In Auto mode, the lights come one when it gets dark ,or it is raining and he vehicle is in drive.  Turn the lights on manually, check the TV tail lights, if they re on, are the trailer lights on?

Cheers