My pac-brake switch is on the floor like an old style headlight dimmer. Do you have the same? There is an air operated ram that opens and closes the butterfly on my unit right at the back of the turbo. I'm not sure if it operates through a relay or not.
Finally Retired-60% Time in Motorhome
2000 Dynasty Regent, 8.3, Banks Turbo, McCabe Racing 5" Diameter Exhaust, 475 HP 1425 Torque 11+MPG towing 05 Pilot 700W solar & E-Bikes