Brake padal pressed , and head lights come on ?

There's a switch on the brake pedal arm that turns the light on when you press the brake pedal.
The switch needs to be adjusted or replaced.
Hope this helps.

Your brake pedal....at the top under the dash a switch attached to the pedal brake pedal switch spring is hooked it might have came of or might need adjustment counterclockwise in the adjustment.adjust and inspect

First thing to check is the switch located on the brake pedal. It should be mounted under the dash and when the pedal arm moves it should push in a plunger, check for proper arm adjustment and check the wires to see if they have been loosened. 

make sure all of your brake light bulb are double element bulb
there is a single element bulb u used insted of a double
google whatbulb.com

The brake pedal switch on most cars or trucks is near the top of the brake pedal assembly where it pivots under the dash. As you move the pedal it releases the switch.

near the brake pedal under the dash

there is a brake switch it might be defective

there is a switch under the dash that when u press brake pedal it compresses switch and turns on light, look under dash and look at arm on break pedal towards the firewall, is switch broken and if not test both wires with probe while pressing pedal and both should be hot while pressing pedal if not bad switch

adjust brake switch on drake pedal for cruise .

no easy one but some main wire under your dash is hook wrong did u have any thing new fit in

Have you checked the switch for power? get a cheap test light and you should have power on one side of the switch all times.If you dont it will be a supply fault eg fuse, fusable link. does every thing else work,intieror lights, clock, haz, horn. if you have power on it check other side of switch when pressing brake padal, if so ceck for power at lamps with pedal pressed. if so check for correct type lamp or an eath problem. see how you go...