Why do Brake lights fuses keeps blowing

SOURCE: my brake lights wont work

Just had a similar problem. Brake (stop) lights and horn didn't work. Couldn't find mention of stop lights in fuse chart. Found horn fuse to be slot 21 in the engine fuse block (not the fuse block in car interior). Replaced 15A fuse and all now ok.

SOURCE: plugged in a trailer and now brake lights and horn don't work

There definitely should be a fuse for your brake lights. It should be inside the car fuse box, but sometimes it'll be under the hood (very rare). There's also a switch above the brake pedal that turns your brake lights on. This switch may be faulty

SOURCE: mazda eunos dash lights and rear lights not working

Check fuse f3 located in fascia fuse box,below steering wheel just above data link connection 15AMP
Fuse under bonnet f7 also connected to dash/rear lights,but if this blows you would have no indicators as well
good luck barry

SOURCE: Why rear brake lights not working on 1990 Mazda

You'll have to inspect the brake light switch at the pedal box assy. Damaged switch or wiring could give the previous symptoms you describe.! Good luck

SOURCE: I'm driving a mazda drifter

Finding wiring diagrams is a difficult thing to do. You can get them but they are expensive. But the most common problem in finding electrical shorts in trucks are usually in the tow package. Do you have a tow package for trailer wiring? If so I would start there. Most of the time it is a shorted wire there. If you don't have a tow package, then try to determine when the fuse is blowing. For an example, when you press the brake pedal, or while honking the horn it blows. If it is when pressing the brake, you will know it is the brake wiring. Or when you hit a bump while pressing the brake. Finding shorts are very difficult sometimes. But finding a good wiring diagram are even more difficult.