brake/horn prank help

[bigt 10+ year member]

ok so my buddy has a 99ish blazer 4dr and i wanna connect his horn to his brake. Whats an easy way to do this. I can figure things out easily but have no car ele background.

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[req 5,000+ posts]

lol yea that sounds pretty easy. if there is a fuse for the breaklight that is //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

if there isnt, you could get an aftermarket horn\siren, and hook it up to the battery and run the ground wire into the break pedal area. hook it inline with the plunger for the break pedal or something so it grounds when the break plunger is pushed in.

 

[KaeZoo 10+ year member]

You need a relay, because the brake light output is positive but the horn trigger is negative. You can probably find both wires under the steering column; the brake wire is white and the horn wire is black. USE A MULTIMETER TO TEST WIRES BEFORE YOU CONNECT THEM!

Wire your relay like this:

85--brake wire

86 and 87--ground

30--horn trigger

87a--not used

When the brake is pressed, it will activate the relay, which will connect the horn trigger to ground.

Jumping fuses won't work because the fuses are in the circuit before the switch. If you test the horn fuse in the vehicle fuse box you'll find it has power all the time. Same with the fuse for the brake light.