This is a DIY for a 03 - 08 Corolla changing the OEM horn to a Dual Electric Horn .
The easy way to do this is with the grille off - Just two screws holding it
Then you can wire it up real simple one is positive the other is ground - Carefully measure the horns so that it can be even - Then ground the ground wire to the vehicle and the positive to the wire that the OEM horn came from .
This is what it will look like and everyone will hear you .
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