If I remember correctly, Pre-facelift W140s had the trunk lid vacuum hooked with the door locks pump, not the doors servo assist pump (as it is operated on later post-facelift models).

Try resetting also the fuse(s) for the door lock/seat lumbar pump. Even if the door locks and lumbar supports work, the trunk lid function might be disabled.

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A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]