1992 F150 with factory AC

So I checked the vacuum diagram under my hood to double check the main vacuum feeds for the EGR and HVAC systems. None of the HVAC vacuum lines were even on the sticker.(apologies for the hard to read sticker)

Everywhere I’ve read said the HVAC needs to be connected to the vacuum reservoir via a 3 prong check valve.(manifold vacuum feed/HVAC/reservoir) however my vacuum sticker has no mention. It just shows the EGR/TAB/TAD solenoids feeding from the vacuum reservoir.

So on my year did the HVAC system just feed off manifold vacuum straight from the top of the plenum with a check valve installed?

 

There is a vacuum reservoir on the side of the evaporator core cover. So the black vacuum line comes off of the manifold, and attaches to the check valve, the perpendicular port on the check valve goes to that reservoir, and the other end goes to the hvac control under the dash. The purpose of the check valve and reservoir is to prevent the air from switching back to defrost when accelerating.

 

What Shagg said sums it up nicely
Vacuum reservoir should be a conventional can on his 92?
On the inner fender
One way valve is the tee

 

Thank you guys for the replies. So the HVAC assembly has a BUILT IN vacuum reservoir inside the unit that is connected to vacuum via the right most black vacuum line by the evap coil?

I was under the impression that the vacuum can on the passenger side fender supplied stored vacuum when needed to the HVAC.

So in short, the vacuum lines should be:

1. Manifold vacuum to check valve

THEN

2. one port of check valve to HVAC controls(left black vacuum line coming from HVAC)

3. last port of check valve going to right most black vacuum hose which is a built in vacuum reservoir on HVAC