One answer is yes, you can buy a rekeyable lock cylinder from the dealer and then you will be able to use the existing key. have yu pulled the inner door panel and tried to rech up and move the locking rods to see if the locks will work manually. On my 1990 325ic I had to repalce the door lock motor on drivers door and the central lock controller (located behind and belwo the left front drivers side kick panel). I bought them used from Bavarian recycle in Sacramento, CA. and after installation all locks work, however, I still cannot lock the drivers door from the drivers door lock (I can unlock thpugh from drivers door lock). I am in process of rekeying the drivers side door lock cylinder and hope that works. Good news is that I can lock or unlock car using passenger side or trunk lock.