More Air Suspension failures

I have a 1999 4.6 HSE. Every 3 months or so I get "EAS Fault". The only way out is a dealer reset, If I don't it drops to the bump stops after about 200 miles without further warning. Error message is "pressure switch not changing state" I have changed pressure switch, air dryer, relay (in relay box). No obvious compressor or valve block problems. I have heard of other RRs being traded in because of failure to find a solution. Surely there must be an answer! Any other ideas please?

Two things I have come across that can cause this problem if the switch has been changed, are compressor worn or a slow leak somewhere. If car is not droping at one side overnight then it would sugest the compressor is on its way out. You could also invest in your own system to set and read faults see www.rovacomlite.com

However electrical problems sound the more likely, bad connections coroded conector etc at air valve box, or bad earth on syatem.