Pressing Brake engages Parking and License plate lights!

MgWms

Bought this older truck for my 16 yr. old son. When taking it for the inspection, the man said it didn't pass. The reason is when pressing the brake it turns on the brake lights, the parking lights in the front, and the lights that shine on the license plate. Another issue...when the headlights are on, and pressing the brake, it does NOT make the brake lights brighter. I am trying to see if we can fix it without taking it to the mechanic. I am the mom, and dad is not in the picture. Is this an easy thing for an amateur to figure out with experienced guideance?

thecardoc3

You have a bad ground connection, possibly a bad socket at the rear of the truck. Instead of the power for the brake lights going to ground, it's back feeding the parking lamp circuit.

MgWms

This is the negative side. (The positive is clean.)

thecardoc3

The ground problem affecting the lights is in the back of the truck. Either one of the sockets that the bulbs go into or the ground wire for them.

That being said, what you have at the battery is a problem in itself and you need to plan on replacing that battery cable. A bolt on ends is at best a temporary solution until a new cable is installed.