OUTPUT SWITCHING MODULES (OSMs): Addressing
WARNING: This page is about a different car, the 1992 Cadillac Allante and 1991 Cadillac Allante. However, it is still accessible from the selected car via links, so may be relevant.
In order for an OSM to know which commands from the BCM it is to respond to, it must have an "Address". The OSMs are addressed by the vehicle wiring harness through the presence or absence of a wire (voltage) on OSM pins C, D, E, or F. Any pin without a wire will have a plastic "Plug" in that cavity or pin location.
Each of these four pins has a different "Value", the total of all the pin values with a wire is the OSM number or address. The OSM "Value" for pin C is 8, D is 4, E is 2, and F is 1. For example, an OSM with a "Plug" at pin C and F and with wires at D and E would be OSM No. 6 (D=4, E=2, 4+2=6). Specific OSM addresses are detailed for each OSM. See Fig 1 .