Dorman 904-393 Diesel Exhaust Fluid (DEF) Heater

Overview of Dorman Diesel Exhaust Fluid Heater 904-393

The Dorman 904-393 Diesel Exhaust Fluid (DEF) Heater is designed specifically for Ford F-350 Super Duty models. This DEF heater ensures optimal fluid temperature for efficient emission control in diesel engines, helping maintain proper DEF system operation in cold conditions.

• Inside diameter: 115 mm for precise fitment
• Single electrical connector with 7 terminals (female connector, male terminals)
• Durable black plastic housing
• Includes mounting hardware for straightforward installation
• Female inlet and outlet fittings for secure hose connections
• Resistor-type level sensor integrated
• Wire colors: black, white, yellow, blue, red, gray with plastic insulation
• Height: 285 mm
• Specific fitment for Ford F-350 Super Duty

Detailed Product Description

The Dorman 904-393 DEF Heater is engineered to maintain the diesel exhaust fluid at an optimal temperature, preventing freezing and ensuring consistent DEF delivery in Ford F-350 Super Duty trucks. Its black plastic housing provides corrosion resistance and durability under harsh engine bay conditions. The heater features a 115 mm inside diameter and is equipped with a single electrical connector containing seven terminals, designed with a female connector housing and male terminals for reliable electrical connections. The unit includes mounting hardware to facilitate proper and secure installation. Both the inlet and outlet fittings are female type, allowing compatibility with the vehicle’s DEF system hoses (hose not included). The integrated resistor-type level sensor helps monitor fluid levels accurately. The wiring harness includes multiple color-coded wires with plastic insulation to ensure safe and organized electrical routing.

Applications and Problem Solving

• Prevents DEF freezing in cold weather conditions
• Ensures consistent DEF flow for emission control compliance
• Reduces risk of DEF system faults and warning lights
• Maintains proper DEF temperature to optimize SCR system performance
• Helps avoid costly repairs related to DEF system malfunctions

Installation Notes and Tips

Installation of the Dorman 904-393 DEF Heater should be performed by a qualified technician familiar with Ford F-350 Super Duty emission systems. Ensure the electrical connector is securely attached and the wiring is routed away from heat sources and moving parts. Use the included mounting hardware to firmly secure the heater in place. Verify that the female inlet and outlet fittings are properly connected to the DEF hoses. Since the hose is not included, inspect existing hoses for wear or damage and replace if necessary. After installation, perform a system check to confirm proper heater operation and DEF flow.

Quality Assurance and Warranty

Dorman parts are manufactured to meet or exceed OEM specifications for fit, form, and function. The 904-393 DEF Heater undergoes rigorous quality control to ensure durability and reliable performance in Ford F-350 Super Duty trucks. This part is backed by Dorman’s limited warranty, providing coverage against defects in material and workmanship under normal use. Refer to Dorman’s warranty policy for specific terms and conditions.