Four Seasons 74798 HVAC Heater Control Valve
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Four Seasons
 Heater Valve

Four Seasons 74798 HVAC Heater Control Valve

Brand Four Seasons 16-1
Product line Heater Valve
Fits —12 vehicles

OE replacement. Vacuum-operated heater valve for a direct-fit repair.

Non-bypass design. Controls coolant flow with a simple, efficient valve layout.

Thermoplastic / steel. Combines durable materials for dependable HVAC performance.

Cross-references Carlson 15137, Carlson 15162 and Four Seasons 74798 for the same application. See all 22.

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Four Seasons 74798 Heater Control Valve

The Four Seasons Heater Valve 74798 is an OE replacement HVAC heater control valve built for vacuum-operated temperature control. It uses a non-bypass design with two hose connectors and a 0.750 in. opening to regulate coolant flow through the heater circuit on select Cadillac applications.

Key Features

  • Vacuum closes non-bypass heater valve design
  • Vacuum operation for HVAC temperature control
  • Thermoplastic and steel construction
  • Two hose connectors
  • 0.750 in. / 19.050 mm opening
  • OE replacement for direct-fit service applications

Product Details

Four Seasons 74798 is part of the Heater Valve line and is engineered as an OE-style HVAC heater control valve for restoring proper coolant routing through the heater core circuit. This valve is used on 1988-1989 Cadillac Commercial Chassis, 1988-1989 Cadillac DeVille, and 1988-1989 Cadillac Fleetwood. For buyers searching for a 1988 Cadillac DeVille heater valve or a 1989 Cadillac Fleetwood HVAC heater control valve, this part number provides a direct reference point for the correct vacuum-operated configuration. This part cross-references Gates 25150 and TYC 30317 for the same application.

Common Uses

  • Restores heater temperature control on vacuum-operated HVAC systems
  • Addresses coolant flow issues through the heater circuit
  • Helps correct inconsistent cabin heat output
  • Replaces a leaking or sticking heater control valve
  • Supports proper operation on Cadillac Commercial Chassis, DeVille, and Fleetwood models

Installation Notes

Verify the valve style, hose connection count, and 0.750 in. opening before installation. Match the vacuum-operated, non-bypass configuration to the original part and confirm hose routing on the vehicle before reconnecting the HVAC system. Use the vehicle’s service information to confirm fitment on 1988-1989 Cadillac Commercial Chassis, DeVille, and Fleetwood applications.

Quality Assurance

Four Seasons 74798 is an OE replacement heater valve built with thermoplastic and steel materials for service on the specified Cadillac applications. The Four Seasons Heater Valve line is focused on replacement HVAC control components that match original equipment function and fitment requirements.

Related reading

This part fits 12 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelSubmodelPositionNotes
1989CadillacCommercial Chassis—N/AHeater Valve
1989CadillacDeVille—N/AHeater Valve
1989CadillacFleetwood—N/AHeater Valve
1989CadillacFleetwoodBaseN/AHeater Valve
1989CadillacFleetwoodd'EleganceN/AHeater Valve
1989CadillacFleetwood60 SpecialN/AHeater Valve
1988CadillacCommercial Chassis—N/AHeater Valve
1988CadillacDeVille—N/AHeater Valve
1988CadillacFleetwood—N/AHeater Valve
1988CadillacFleetwoodBaseN/AHeater Valve
1988CadillacFleetwoodd'EleganceN/AHeater Valve
1988CadillacFleetwood60 SpecialN/AHeater Valve
Directly replaces or cross-references 22 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
Carlson — 15137Carlson — 15162Four Seasons — 74798Gates — 25150Global Parts Distributors LLC — 8211254NGK — 5944TYC — 30317UAC — HV539215539224629280102031600546601268717479811174798V1916936925532790CWK801020H570H6311HV9453WV292