Hi- after some help please.
Our caravan brake lights don't work with the cars- all other lights work fine, and the brake lights on the caravan work with a test rig, but not with the car brakes.
Any ideas?
Many thanks

I recently had this problem with left hand indicator & I found the problem was with the pins on 13 pin plug not pushing in fully. Try removing the outer case from the plug & then plug it in fully to see if it works then. That's how I located the problem. When the plug was pushed into the socket, the pins on the plug were being retracted into the body of the plug, preventing the connection. I fixed it with a small s/t screw going through the outer casing into the pin section, preventing it from retracting.