OBC Code disabler wires?

[L8APX]

Group,

I am looking to put a kill switch on my girl's 1997 328IS. On my E30M3 I was able to put a switch in that grounds out the wire the On Board Computer. The way the code system in your OBC is that it will ground out a wire to kill the fuel pump. Putting a switch with a grounded wire on this OBC wire does the same thing as putting in a code.

So basically if anyone has wiring schematics for the OBC and know what wire needs to be grounded out to kill the fuel pump let me know. ( A pic of the schematics and the color code for the wire would help me out big time.)