7 pin, 13 pin adventures

Hello folks

On a previous discussion I confessed to driving the car away with the elctric cable still attached to the car.

THe caravan is almost 20 years old, it's an old 7 Pin electric cable, the socket of which was decapitated from the cable in the 'incident'.

I took the opportunity to replace it with a 13 Pin socket, which matches the electric plug on the car, so no more swaering when trying to fit a 7 pin plug into a 13 pin power supply and wondering why the brakes lights are flashing when I turn the indicators on.

I tested the connections yesterday, and all good.

Mostly.

Indicators?  Check.

Hazards?  Check.

Brake lights?  Check.

Car headlights on?  Check, though the brake lights are also on

Car headlghts on and brake peddle depressed?  Err, why did one of the lit brake lights go off, and the other one still stay on?

Not a terrible state of affairs as long as I don't drive at night (not a chance).

also, the caravan has no reverse light, or fog light.  Not that I'll ever be reversing.  It's like steering the Queen mary.

Thoughts?

Thanks