612 vario air handbrake

[papsck]

Hi can anyone help have a 612 vario converted to campervan these vans have air operated handbrake.Yesterday started up pressure built up released brake,moved van. This morning started van waited for lights to go out to release handbrake but lights wont go out handbrake wont release.Later on after investigation 12v isnt reaching compressor so put portapak straight to compressor to release brake so i could move it.So does anyone have electrical schematic as there is loads of solenoids/pressure swithes or even where fuse might be as all fuses i can find are ok,anyone had same problem?Paul