On the '88 LSC, the module in the trunk.
Turn ignition switch off.
Turn air suspension switch off (That switch is near / above the spare tire, behind the wall carpeting. There's a little hole cut in the carpeting for access...)
If you don't turn it off whenever you work on it, anything might happen, like the car suddenly dropping to the concrete for no reason, and squashing the neighbor's cat..
Remove left side of trunk compartment trim panel.
Disconnect wire harness from module.
Remove the three attaching nuts.
Remove module.
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I dunno how familiar you are with this system, but that module is capable of running a self-diagnostic test of the entire air-suspension system. (It does a series of tests.. Raise Rear, Lower rear, raise right corner.. run the pump.. all sorts of things..)
If you wanna know how to initiate the test, say so..
