Air Suspension Has A Mind Of Its Own
I own a mark 7 LSC that was doing similiar up /
down cycles whenever it feels like it problems --
The only sure way to tell if bags are leaking is to
get it pumped up to ride height and
DISCONNECT THE BATTERY --- this is due to
several components ( like solenoids and module ) that have
battery power through the fuse link at the starter
relay that is hot at all times regardless of the
suspension switch position in the trunk -- this
will eliminate any possible shorted wiring / bad diodes
causing unwanted movement--- let it sit at least overnight
or a couple days if you have the time
-- if you have leaking bag / solenoid or seals it will show itself --
To check individual lines -- disconnect them at the filter and
at each soleniod and put rubber cap on one end ( available at any auto parts store )use a vacuum tester on the lines -- if it pumps up and
holds vacuum ok then your lines are not the problem.
This system also knows when you have the drivers door
open or closed and runs raise/ lower schedules accordingly
( like bag fill schedule / self testing mode - etc )
Any problems with the courtesy lighting systems or
door jamb switches can also mess with the suspension --
The factory manual has pages and pages of multi-meter testing that
should be done prior to changing any big bucks items --
See if you can get your hands on one for your ride --
Hope this was of some use - I have over 30 yr as a mech and
This one drove me insane before I found the messed up wiring
from a prior front end collision.
GOOD LUCK & HAPPY HUNTING
Walt Tallman
Tallman910@aol.com
