Guys thanks for the replies so far. Sometimes the suspension will stay up fine for 24 hours or more, and we have a steep driveway so it's under pressure from weight transfer.
I've inspected the sensor arms and they are undamaged and I searched this site but the search feature misses post sometimes.
I'll tear into the system this weekend, my suspicion is a solenoid controlled relief valve is sticking open sometimes, but I don't have a shop manual for the system so I'm flying blind at this point.
I'm out of warranty and don't want the dealer to just drop in a new system for 2K+ as an easy fix (for him) if it's just a valve. I've got a full shop and experience, hell if I have to I'll make a new part on my lathe.
