Compressor clutch will not engage, and horn only works intermittently

Hello! Recently the A/C compressor started to only engage about 70% of the time, and we would have to hit the button on and off again to get it working. I made an appointment to have it looked at, but a few days before they could see me, we smelled a burning smell in the cabin and the A/C was no longer blowing cold air. That same day, after getting home I noticed my horn didn't sound when I clicked the lock button twice, but when tired it again it worked the second time. I opened the hood to see if the clutch was engaging when the A/C button was pressed (the light turns on) but it did not.

When I took it to the dealer the horn had started only working sporadically and still not clutch engaging, and they said I need a whole new compressor but can't seem to relate the horn issue in anyway. I asked about the relay and they kind of answered but didn't? I'd obviously like to try the small things before shelling out the money, and I'm not confident they feel the same way.

I tried to locate the fuse diagram, but it seems to be a myth. I cannot figure whether there is an A/C clutch relay and, if it does exist, where exactly it would be located. I think I narrowed it down to a 645 over the driver's side cabin fuse panel, but I'm not 100% sure.

Any help on things to check (and where they're located) before paying for the compressor replacement would be appreciated.