ASC+T won't disable on E34 525

I've got a 95 E34 (525ia) with 98k miles. When I press the ASC+T
switch to disable the ASC+T, nothing happens. The light is working
since it comes on briefly during startup. I need to be able to
disengage ASC+T to pass emissions here in Ct on the dyno. Is there
some common failure that can be fixed, or a way to disable the system
to go through the dyno test?
Thanks.