I changed the bulbs for the tail lites now they go out when i apply the brakes, any reason? Does the brake bulb differ from the tail lite?

SOURCE: upper middle brake lite replacement 2006 hyundia sonata

ON MY HYUNDIA, IF YOU OPEN THE TRUNK AND LOOK UNDER THE LIGHT, YOU WILL SEE 2 NUTS THAT ARE RECESSED UP UNDER THE LIGHT. THAT MIGHT HELP.

SOURCE: tail light out replaced both brake & tail lite bulbs nothing

It sounds like your brake light switch is out.  It's located on the brake pedal and is relatively easy and cheap to replace.  Let me know if you have any questions.  Thanks for rating my response and for using FixYa!

SOURCE: I have a 2005 GMC

Since the high mounted brake light works you know that the brake light switch is working. Now you need to check the brake light bulbs in the rear tail light assemblies. The brake lights are separate from the tail light (parking or running lights). There are two screws that hold the rear light assemblies in place.