Diff lock light and Fuel Filter..

[Raider TD5]

Hey PPl.. I am a newbie here! I own a Defender Tomb Raider Edition TD5 2001. and i have a few questions.. My diff lock light doesnt come on altho the diff lock works 100%.. i took the wires off the light switch in the transfer box and connected them together and the light went on.. so i suppose that switch is faulty.. its in a veryy tight location so can it be changed with the transfer box in the car?? Secondly... i wanna change fuel filter on my car... i know my cars and tech stuff reallly well... is the change a simple filter change?? or do i have to watch out for sumthing?? Will i have to bleed the fuel system? how? CHEERSS!!

[Raider TD5]

Can some pleasee reply to my msg??

And if any can give me the following part numbers??

Car is a TD5 2001 Defender 110 4 doorPickup., with air con and power steering, R380 Gearbox.

1. Differential lock light switch.
2. Valve cover gasket.
3. Right rear dool seal
4. Serpentine belt.

And would any one know where can i find my cars color code??
Thanks.