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Four Seasons 74646 HVAC Heater Control Valve
| Brand | Four Seasons 74646 |
|---|---|
| Description | Cable Operated Open Non-Bypass Heater Valve |
| Hose Connector Quantity | 2 Connectors |
| Material | Plastic |
| O.E. Replacement? | Yes |
| Opening B IN | 0.625 |
| Opening B MM | 15.875 |
| Opening IN | 0.625 |
| Opening MM | 15.875 |
| Operation Type | Cable |
| Style | Non-Bypass |
| Type | Heater Valves |
| Product line | Heater Valve |
| Fits | Toyota · 3 vehicles |
OE replacement. Cable-operated heater valve for straightforward installation.
Non-bypass style. Controls coolant flow without routing it around the valve.
Plastic construction. Lightweight design with two hose connectors.
Cross-references Four Seasons 74646, Quality-Built 15106 and 246140 for the same application. See all 14.
Four Seasons 74646 Heater Valve Overview
Four Seasons 74646 is an OE replacement HVAC heater control valve built for cable-operated temperature control systems. It uses a non-bypass design with two hose connectors and a 0.625 in. (15.875 mm) opening, making it a direct-fit service part for restoring heater coolant flow control.
Compatible with 2001-2003 Toyota Sienna heater valve applications, this Four Seasons Heater Valve line part is built for straightforward replacement in the HVAC temperature control circuit. The Four Seasons 74646 is a practical choice when the original valve no longer opens or closes correctly.
Key Features
- Brand: Four Seasons Heater Valve
- Part number: 74646
- Cable-operated open valve design
- Non-bypass style heater valve
- Plastic construction
- OE replacement part
- Two hose connectors
- 0.625 in. / 15.875 mm opening
Product Details
This HVAC heater control valve regulates coolant flow through the heater circuit based on cable input from the temperature control system. The cable-operated, non-bypass configuration is used in applications where the valve directly opens and closes flow rather than routing coolant through a bypass path. For 2001-2003 Toyota Sienna models, the Four Seasons 74646 supports proper heater system operation when the original valve is worn, sticking, or leaking.
This part cross-references Quality-Built 15106 for the same application.
Common Problems It Can Help Solve
- Heater output stuck on hot or cold
- Coolant flow not responding to cabin temperature control
- Leaking heater valve housing or connections
- Sticking or seized cable-operated valve movement
- Loss of heater performance in 2001-2003 Toyota Sienna models
Installation Notes and Tips
Verify hose routing, connector count, and opening size before installation. Confirm the cable-operated control linkage moves smoothly and that the replacement valve matches the original non-bypass configuration. After installation, check the cooling system for leaks and confirm heater operation across the full temperature range.
Quality Assurance
Four Seasons supplies HVAC temperature control components as OE replacement parts, and this heater valve is built to match the original application requirements for fit and function.
| Year | Make | Model | Position | Notes |
|---|---|---|---|---|
| 2003 | Toyota | Sienna | N/A | Heater Valve |
| 2002 | Toyota | Sienna | N/A | Heater Valve |
| 2001 | Toyota | Sienna | N/A | Heater Valve |
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