Those switches are most likely always on switches so when they are pressed they are off. So shorting it would show if it is the switch but I would still check it with the multimeter before you buy more parts. Don't throw parts at it if it isn't the problem.
Green 2000 SVT #1166
mods-K&N and Custom heat shield, optimized y pipe, Magnaflow center resonator, DMDhttp://www.geocities.com/savinoss/Cars.html
-Wifes car 99 Mystique V6 5 spd
