Not your problem; your gaffers should call the fitters out to wherever you are - fuses shouldn’t blow for no reason, so that underlying problem needs to be looked at
pull down the panel or what ever the fuse box is behind. And hopefully on the back your find pictures and fuse numbers if that helps.
Or failing that just pull each fuse and see which ones blown
On side note if horn doesn’t work that’s technically a defect and shouldn’t be driving.
Unless of course it happened during your shift in which case you have to get ot repaired as soon as.
Think your within your rights to forget all your days work bring it back to yard n swop trucks.
In reality you probably won’t