That switch on the MC is a cut off if the brake light switch fails,you can put a jumper wire in the connecter and see if it makes a difference.I have mine jumpered all the time as this is the switch that causes all these trucks to catch on fire.
Cheers Ed
If you are refering to the switch on the end of the master cyc it is for the cruise control,has nothing to do with the brake light.Try on hooking the wire on the park brake lever and see if it goes out.
Cheers Ed
I had this mod on my 96 for a while but did not like it.It made the idle kinda choppy and i could not see that it done anything for power or mileage.
Cheers Ed