fault on zig unit

Hi
I seem to have a fault on the zig unit which is the original one a MC4000M, but not sure yet, on 12 volts the lights work ok, the water pump is good, however the water level meter does not move even when turning the small adjustment screw but the back light is working, the battery status lights does not come on when button is pressed, and when trying to ignite fridge on gas the ignition switch come on and then slowly goes off it does not try to ignite no sounds or visual flashing of switch, I have looked at the zig unit and all I have found is a fuse which has a slight crack in it, havent got one to replace it yet but could that cause the problem, any help is most appreciated 
mike 
vwt4

Hi Sorry no one has come up with an answer.
Not my model and I am away from mine. I would change that fuse. Have you a multimeter? They are cheap and worthwhile for getting info,even if you only pass the info on the the Forum.
Does anything work on mains hook up?

Hope this helps

Regards

Mike

Have you removed the unit from the wall ?   On the back of these there are some Lucar connectors which are riveted in place and can break or come loose with time. If this is the case easiest cure some is small brasss screws and nuts. Not saying this is the cause but worth a look