I pulled the obc and sunglass holder out of my '94 325i and found this part sitting above the transmission tunnel: 64 11 8 391 512. By the starting number looks like it has something to do with the heater system...but can't figure out what it is. It's a black box about 1"x3"x5".
<span style='color:green'>1994 325i </span>- - - 75,000 mi.
No mods - - - very happy as is!
<span style='color:green'>1995 525i </span>- - - 154,000 mi.
No squeaks or rattles... unreal!