Product Description
DORMAN 904-632 DIESEL EXHAUST FLUID (DEF) HEATER FOR 2011 GM 6.6L DURAMAX LML
The Dorman 904-632 DEF heater assembly is an upgraded OE FIX replacement designed for 2011 GM trucks equipped with the 6.6L Duramax LML diesel engine.
This diesel exhaust fluid (DEF) heater restores proper DEF system operation while addressing common OEM heater failures caused by fluid intrusion inside the factory assembly.
Engineered to match OEM fit and function, the Dorman 904-632 helps maintain proper DEF temperature regulation, supports emissions system performance, and helps prevent DEF-related warning lights, heater faults, and cold-weather DEF system issues.
FEATURES
- OE FIX upgraded DEF heater assembly
- Designed to address common fluid intrusion failures
- Restores proper DEF system operation
- Direct-fit replacement for OEM assembly
- Cyclical heater fatigue tested for durability
- Electronic DEF level sensor compatibility
- Includes mounting hardware and cap
- Engineered for long-term reliability
FITMENT
- 2011 Chevrolet Silverado 2500HD 6.6L Duramax LML
- 2011 Chevrolet Silverado 3500HD 6.6L Duramax LML
- 2011 GMC Sierra 2500HD 6.6L Duramax LML
- 2011 GMC Sierra 3500HD 6.6L Duramax LML
Fitment Note: Verify OEM part number and DEF tank configuration before ordering.
WHAT'S INCLUDED
- 1 DEF heater assembly
- 1 DEF heater cap
- Mounting hardware
COMMON SIGNS OF A FAILED DEF HEATER
- DEF warning lights
- Check engine light illumination
- DEF heater circuit fault codes
- Reduced power or limp mode conditions
- Frozen DEF during cold weather operation
- DEF system communication faults
OE CROSS-REFERENCE
- GM 22783125
- GM 22902619
- GM 23379346
- GM 84412929
INSTALLATION NOTES
- Disconnect batteries before installation
- Inspect DEF tank and wiring connectors for contamination
- Verify DEF fluid quality before reassembly
- Clear diagnostic trouble codes after installation
- Check DEF system operation after startup
SPECIFICATIONS
- Brand: Dorman
- Part Number: 904-632
- Product Type: Diesel Exhaust Fluid (DEF) heater assembly
- Engine Compatibility: 6.6L Duramax LML
- Vehicle Compatibility: 2011 Chevrolet Silverado and GMC Sierra HD
- Housing Material: Plastic
- Housing Color: Black
- Electrical Connector Gender: Female
- Electrical Connector Quantity: 2
- Electrical Connector Terminal Gender: Male
- Electrical Connector Terminal Quantity: 2 and 7
- Inlet Fitting Type: O-Ring
- Outlet Fitting Type: O-Ring
- Level Sensor Type: Electronic
- Mounting Hardware Included: Yes
- Package Contents: Heater assembly, cap, mounting hardware
- Package Quantity: 1
- Packaging Type: Box
- Fitment Type: Vehicle specific
- Wire Insulation Material: PVC
- Condition: New
FAQ
What does the DEF heater do?
The DEF heater prevents diesel exhaust fluid from freezing during cold-weather operation so the emissions system can function properly.
What makes this an OE FIX upgrade?
Dorman redesigned the heater assembly to help address common OEM failures caused by DEF fluid intrusion.
What are symptoms of a failed DEF heater?
Common symptoms include DEF warnings, heater fault codes, limp mode conditions, and cold-weather DEF system failures.
Is this a direct-fit replacement?
Yes. Dorman 904-632 is engineered to match the original DEF heater assembly fit and function.
Does this include installation hardware?
Yes. The assembly includes mounting hardware and the DEF heater cap.
