Coupe what should i do with the coupe ??

[drifttuner]

after i had another go yesterday before it got to dark and the alarm kept blaring when i turned it over (batt is almost dead) near my fuse box i saw a white wire harness that had been undone. i refitted it and now the central locking is working by the fob and sealtbelt warning light now works i wonder what else this powers ??? hopefully its was my long legs that caught it as dnt want to think the last owner do it to hide a fault

anyway i found out where the humming was coming from its one of the connectors on top of the intake pipe where it meets the block. also i took off the air filter to smell for unburnt petrol but cant smell a thing. so could it be a fuel relay, or pump if anyone could advise me that would be great as xmas is here i cant get a mechanic til next week