This Service Information bulletins supersedes S.I. 72 04 96 dated November 1997.

SUBJECT Seat Belt Buckle Switch, SRS Fault Codes 16/17 or 24/25
MODEL 3 Series (E36), 5 Series (E39), 7 Series (E38) produced up to 09/97
Situation: The SRS airbag warning light stays illuminated, and the following fault codes are stored in the SRS Airbag Control Module fault memory:
On vehicles equipped with ZAE system,
-- "24 - Driver’s seat belt buckle switch", or
-- "25 - Passenger’s seat belt buckle switch"
On vehicles equipped with MRS system,
-- "16 - Driver’s seat belt buckle switch", or
-- "17 - Passenger’s seat belt buckle switch".
Important: These faults have no effect on the airbag deployment function.
Cause: Defective printed circuit board or contacts of the seat buckle switch, are causing resistance values to fluctuate under mechanical load.
Correction: Perform diagnosis with DIS/MoDiC tester utilizing the corresponding test modules. On a customer complaint basis only, and if Fault Codes 16/17 or 24/25 are logged in fault memory of the control unit, replace the respective seat safety buckle assembly with the improved part. The appropriate part number can be located in the BMW Electronic Parts Catalog (also, refer to the Parts Replacement Table below). Clear the fault memory of the airbag control module
The safety belt latch with the improvements to the mechanical microswitch can be identified by the date 01.09.1997 or higher, stamped on the receptacle housing. Furthermore, since September of 1997 a Hall Effect sensor replaced the mechanical switch in the seat latch assembly.
For details on replacing the front left or right safety belt buckle, refer to repair instruction RA 72 11 030.
Observe all relevant safety information when performing repairs to the Airbag System.
Always follow the "Safety Regulation for Handling Components of the Airbag System" (TIS 32 34...).
Important: Since March of ’97 production, all E36 models are fitted with the pyrotechnical tensioner units, which replaced the mechanical type. In case of replacement, only the safety belt buckle with pyrotechnical tensioner must be used on those vehicles (P/N 72 11 8 221 013, and 72 11 8 221 014).
1. E36 belt buckle with pyrotechnical tensioner
2. E36 belt buckle with mechanical tensioner
PARTS INFORMATION,Model....product.tensioner/switch p/n......remarks
E 36/2/4/5..09/93 to 03/97
for manual seats: 72 11 8 167 711 left, 72 11 8 167 712 right
Mechanical tensioner,mechanical switch (3 wires,3 pin connector); part manufactured after 01.09.1997
for electric seat: 72 11 8 167 715 left, 72 11 8 167 716 right
E 36/2/4/5 From 03/97: 72 11 8 221 013 left, 72 11 8 221 014 right, Pyrotechnical tensioner,initially mechanical switch (3 wires, 4 pin connector), replaced with Hall sensor (4 wires, 4 pin connector)
Z3 From 01/96: 72 11 8 221 013 left, 72 11 8 221 014 right, same as above
E38/E39 Up to 03/97: 72 11 8 233 537 left, 72 11 8 233 538 right,Pyrotechnical tensioner,mechanical switch (3 wires,3 pin connector); part manufactured after 01.09.1997
E38/E39 From 03/97 to 09/97: 72 11 8 221 009 left, 72 11 8 221 010 right, Pyrotechnical tensioner,initially mechanical switch (3 wires, 4 pin connector),replaced with Hall sensor (4 wires, 4 pin connector)

Defect Code 65 77 98 96 00
Labor Operation: Replacing front left or right buckle assembly with seat belt pretensioner
SI Seat Belt Buckle Switch, FC 16/17 or 24/25, 23.07.2002

http://www.netropy.com/stuff/SI-720496.PDF