i just got a 1999 chevy hd 3500 diesel, i think is a 6.5
when im drive it the turbo doesnt kick in
i have a vacuum hose (black) from the turbo to a sensor and from the sensor to intake i think (orange), the intake have vacuuum but the sensor does not send vacuum to the turbo.
im thinking the turbo should have vacuum when you step on the gas????
why is my sensor not working, should i have power and ground at all time at the sensor?

any help will be appreciated

thanks G