Disconnected engine bay wires? Help Please

Right i have a few wires that are not connected and cant see where they go, everything works ok on my car apart from dash lights and oil light but would still prefer to know what these do, its a 1.8 gti

1. quite a large black cable, bit like a battery ground connected to one of the bolts on the coil and not connected the other end?
2. Light brown wire with a black spade connector to the right of the head near top gearbox?
3. Red + white wire near left hand side headlight as you look from the front also a blue + white one in the same place?

Any help where these should be connected would be much appreciated and what they ate for

Thanks

1. other end goes to one of the bolts on the rocker cover/head

2. sure its not yellow? if it is thats the pressure switch on the side of the head

3. not sure on this one, pics? might be outside air temp sensor?

I know the brown is ground  (earth )