Suburban Vents

[Shikaroka]

Where does the air come from for the heater-A/C vents that are in the headlinder just above the front seats? (The ones next to the rear controls)
These vents on my Suburban never seem to blow warm air, while the floor vents will a little.
And ideas on troubleshooting these guys?

[kaylabryn]

All the air comes from the air handler in the back on the right side (looking forward) passenger side in the U.S.. There is two cores back there if you have dual a/c and heat. There is also a servo motor that rotates a flap between the evaporator on the a/c and the heater core. There is also another one that controls the air to top vents and the bottom vent by the right rear door. The side panel will come off to look at all this pretty easy. The first time it might take a little while. Hope this helps.

[Shikaroka]

That's a start. Thanks!
I'll pull off the covers when I get the chance.