Coolant Heater Inoperative

Coolant Heater Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The optional coolant heater operates using 110 V AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather. There is an internal thermal switch in the power cord that prevents operation above -18°C (0°F). The coolant heater helps reduce fuel consumption when a cold engine is warming up. The unit is equipped with a detachable AC power cord. A weather shield on the cord is provided to protect the plug when not in use.

Reference Information
Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference

Component Connector End Views Connector End Views By Name
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Wiring Repairs Wiring Repairs

Circuit/System Testing

Note: The power supply cord will read Open due to an internal thermal switch if the ambient temperature is above -18°C (0°F).

1. Test the engine coolant heater for an open or short to ground.

• If open or shorted, replace the E19 coolant heater.

2. If the E19 heater tests normal, replace the coolant heater power cord.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Engine Coolant Heater Replacement (LFW,LFX) Engine Coolant Heater Replacement (LFW,LFX)
* Coolant Heater Cord Replacement (LFW,LFX) Coolant Heater Cord Replacement (LFW,LFX)