Hi all, major electrical faults r/r hse

hi all, seem to be having major electrical faults with the r/r hse. the car has sat for about 8 weeks then at the weekend i got it started but it flashed up electrical fault, not petrol,temp,speedo,elec windows or rev counter working. took it out for a spin and everything else seemed allright.
the the usual happend when driving home from work in the blizards air suspension lights started flashing and the car dropped down to the bump stops, i have got some manual valves for the air sus to get it going again and bought a fuse board to replace the old one, any advice would be great.(hoping its not the becm)

from reading some other posts, check that the battery is ok if its on its way out it can throw up electrical faults,other than that i aint got a clue electrikery aint my thing but its a start for you or find some one with testbook

thanks for that, i read if the fused boards goosed it can cause the battery to drain but i heard that a faulty becm can cause this too. cheers