I cleaned my trunk lock button with wd-40 then used a graphite lubricant. Then used Tri-flow lubricant (works on guns) on the lock mechanism (also sprayed w4-40 on first) in the trunk. Then I did the same for the other door locks. Seemed to resolve some central locking issues i had with the passenger door not locking.
Thanks,
1995 525i Auto, M50TU 2.5L, EAT chip, 1/95 build, USA, 205/65/15 tires, ASC+T, HID, lumbar, EC Mirror, BMW Alpine 5 radio with BMW-Pioneer CD Changer, abt 236k miles, Oxford Green/Parchment