i have a 2005 Mazda b4000 and the break light wont work. the parking lights come on and the turn signals all work. i have replaced the switch and checked all the fuses and still nothing. Any suggestions?

 

What switch did you replace?

The Multi-function switch(turn signal arm) is where the brake light switch sends 12volts when you press down on the brake pedal, that power is sent from this switch to left and right brake lights.

It runs through there so turn signal can override brake light on that side, assuming one bulb is used for brakes and turn indicator.

 

i replace the one on the pedal the (break light on/off)

 

i also checked the voltage to where the fuse plugs in and i got a reading then i checked for voltage on the red a green wire on the brake light on off switch plug and got nothing

 

Fuse #19 20amp is the brake pedal switch fuse, it will have power key off or key on.

Check if brake light on the back of the cab comes on, it is powered directly from the brake pedal switch, doesn't go thru multi-function switch.

Battery-------Fuse #19----------brake pedal switch----------Cab brake light-----Ground

 

thanks that worked i only checked the 2 amp fuse forgot to consider that the cruise control fuse could be stopping it

 

Good work on getting it working

On a wiring diagram I saw for 2005 Mazda B4000, fuse #19 is main Brake light fuse, odd it says Cruise Control.
The brake light coming on(getting power) will cut off the cruise control, and I guess it would make sense to power both from the same fuse, i.e. if brake light power was gone you wouldn't want cruise control to work because the main cut off for it is not working.