Maximum Heater Output
Engine coolant is delivered to the heater core through two heater hoses. With the engine idling at normal operating temperature, set the temperature control knob in the full hot position, the mode control switch knob in the floor position, and the blower motor switch knob in the highest speed position. Using a test thermometer, check the temperature of the air being discharged at the HVAC housing floor outlets. Compare the test thermometer reading to the Temperature Reference Chart.
| Temperature Reference | |||||
|---|---|---|---|---|---|
| Ambient Air Temperature | 15.5° C (60° F) | 21.1° C (70° F) | 26.6° C (80° F) | 32.2° C (90° F) | |
| Minimum Air Temperature at Floor Outlet | 52.2° C (126° F) | 56.1° C (133° F) | 59.4° C (139° F) | 62.2° C (144° F) | |
If the floor outlet air temperature is too low, refer to COOLING to check the engine coolant temperature specifications. Both of the heater hoses should be hot to the touch. The coolant return heater hose should be slightly cooler than the coolant supply heater hose. If the return hose is much cooler than the supply hose, locate and repair the engine coolant flow obstruction in the cooling system. Refer to COOLING for the procedures.