Inside light/alarm system

I have a 1994 E320. Great car but it has a few weird things going on with it.

The alarm will come on for no reason

The inside light will come on by itself. When the inside light does come on the seatbelt light and the door light will come on as well .When I manually turn the inside light off the seatbelt light still flashes.

Any ideas how to fix it or what to look for? Thanks for your help.

this seatbelt light is also in my merc and should come on by itself after all, it is a safety feature and shouldnt be turned off. if you like you can follow your user manuals instrucitons on removing the seatbelt warning lamp and remove the 3 bulbs, this will stop it lighting.

the lights coming on problem is a switching and or earthing problem, so order the two swithes (located beside the dash where the door hinges are) from your dealership and when fitting them gently pull the wire out about 6 inches and wrap it in insulating tape on each side.

for the alarm disconnect the battery and wiat i min, connect agian and the problem will be solved. (the backup alarm will sound but it is quiet so dont worry and check that your radio isnt keycoded before you disconnect the positive battery terminal.)