Horn Sounds Continually until disconnected

Audio system, a/c ,digital screen, etc.
doesn’t come on, no lights nothing.
But dash gauges are all good.

Radio wont turn on neither will aircons or anyother controls there unless radio is on says error if not somtimes wont even turn in to the point it says the error any ideas? and also need a fuse box guide as it dont have one on cover also wanna know whats that brown plug ment togo to as i found where it goes but nothing there to connect

A/C not working. Not cold, wanting to have a few ideals how to test it, apart from trying the Fuze? Pls

I have no sound but all the fuses are good. It’s got a aftermarket head unit. It originally had sound one of my speakers blue and then I put a new one in and now I’ve got no sound at all. Also got a sub and amplifier just wondering if anybody could help thank you.

The aircon fluctuates when the A/C is on and doesn’t get past 12 degrees Celsius. When the heater is on it takes forever to get warm ish and doesn’t get hot. Replaced the Compressor, T-X valve, been regased and apparently no leaks

Over heating fan's won't switch on or work on low only in high when the air conditioning is on

No horn or alarm working on car

Power window circuit breaker blown how can I bypass it to get windows working

Replaced alternator and when we started it back up we had bugger all replaced fuses even though none were blown please help

When raido tirns on it displays an error what would it be also need a guide on fuses as cover dont show one

8volts from a battery can and has run my au falcon in accessories mode and has ran my radio before, same situation, but radio doesn’t turn on, replaced fuses 3 times. Is it because of the battery

Sunroof not working looking for fuse yo see if bolwen