What fuse is for the horn
If you have the owners manual, look there. If not just pull the fuses until you find the bad one.
Try #11, a 20A fuse. That's what it is on my '91 and I think the electrical layout is the same as your '88.
All else fails do a Google Search and just put the name of your vehicle you know what brand it is Pontiac Firebird and the year and then put fuses and it might give you an idea the fuses in the box amperage number excetera and what goes where.
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