1996 Chevrolet Lumina Q&A

1996 Chevrolet Lumina Question: Accessory Vacuum check valve?

What is the function of the Accessory Vacuum check valve? For the heck of it I replaced it and all of a sudden my vents in the cabin for air/heat/AC are now WORKING? -
Answer 1
On some vehicles, engine vacuum is used to operate the cruise control and heater/AC mode and temperature function. If vacuum is lost these systems will not function correctly. The check valve will is a one way valve that allows vacuum to be supplied and also traps vacuum for the accessory system during times of low engine vacuum - under heavy engine load, when the throttle is open. -