Vacuum System Control Schematic
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
Heater Only
| Vacuum Valve Switch Operating Chart | |||||||
|---|---|---|---|---|---|---|---|
| Vacuum Hose Connector | Port Number | Off | Vent | Bi- Level | Heat | Blend | Defrost |
| A/C Open | 1 | Vent | Vacuum | Vent | Vent | Vent | Vent |
| Defrost | 2 | Vent | Vent | Vent | Vent | Vent | Vacuum |
| Bi- Level | 3 | Vent | Vacuum | Vacuum | Vent | Vent | Vent |
| Recirculation | 4 | Vent | Vent | Vent | Vent | Vent | Vent |
| Heater | 5 | Vacuum | Vent | Vacuum | Vacuum | Vent | Vent |
| Vacuum Source | 6 | Vacuum | Vacuum | Vacuum | Vacuum | Vacuum | Vacuum |
Heater and Air Conditioning
| Vacuum Valve Switch Operating Chart | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Vacuum Hose Connector | Port Number | Off | MAX | Normal | Bi- Level | Vent | Heat | Blend | Defrost |
| A/C Open | 1 | Vent | Vacuum | Vacuum | Vent | Vacuum | Vent | Vent | Vent |
| Defrost | 2 | Vent | Vent | Vent | Vent | Vent | Vent | Vent | Vacuum |
| Bi- Level | 3 | Vent | Vacuum | Vacuum | Vacuum | Vacuum | Vent | Vent | Vent |
| Recirculation | 4 | Vent | Vacuum | Vent | Vent | Vent | Vent | Vent | Vent |
| Heater | 5 | Vacuum | Vent | Vent | Vacuum | Vent | Vacuum | Vent | Vent |
| Vacuum Source | 6 | Vacuum | Vacuum | Vacuum | Vacuum | Vacuum | Vacuum | Vacuum | Vacuum |