Earth Points and Electrical Faults

[Lew_Derv_T]

so i have a few faults on the car:
Horn doesnt work
revs work when they want to
central locking is broken (which isnt a problem until i realised my boots always open)
interior lights flash when the doors open on the door setting
indicating right or left and hazards come on( asin they both flash not the actual hazard light flashes)..

i have read guides, reviews and blogs how to fix the central locking and the only thing i can take from it is a broken wire in the door which i have to take out to look (quite a big job so itl wait)

with the horn i can hear a click so is that the relay? in case could it be a faulty horn?

with the revs could it be a faulty earth? where is this? or a possible fix?

with the indicating im assuming its also the relay as they both work together just not seperately?

with the interior light could it also be a dodgy earth as my sunroof is fine no leaks.

any earth points i can check that always go wrong? possibly point me in the right direction? maybe a product i can buy and where to get it from..

any help will be hugely appreciated so i can hurry up n get my arse on the road and come to some meets

thanks for reading