Ambient Air Temperature | Heater Air Temperature |
|---|---|
-18°C (0°F) | 54°C (130°F) |
-4°C (25°F) | 59°C (139°F) |
10°C (50°F) | 64°C (147°F) |
24°C (75°F) | 68°C (155°F) |
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Heater Blower Controls System Check? | -- | Go to Step 2 | |||||||||
2 |
Is the airflow high? | -- | Go to Step 3 | Go to Step 21 | ||||||||
3 | Inspect the blower speeds for a change in the airflow. Does the speed of the airflow change? | -- | Go to Step 4 | Refer to Heater Blower Controls System Check | ||||||||
4 |
Caution: The cooling system is pressurized when hot. Is the heater temperature low according to the chart? | -- | Go to Step 6 | Go to Step 5 | ||||||||
5 |
Does the condition persist? | -- | Go to Step 6 | |||||||||
6 |
Does the temperature valve appear to be operating? | -- | Go to Step 7 | Go to Step 18 | ||||||||
7 | Verify the temperature valve operation. Is the temperature valve operating? | -- | Go to Step 9 | Go to Step 8 | ||||||||
8 | Inspect for the following conditions. Repair the components as needed:
Does the condition persist? | -- | Go to Step 9 | |||||||||
9 |
Are both hoses warm? | -- | Go to Step 10 | Go to Step 13 | ||||||||
10 | Inspect the thermostat for the following conditions:
Is the installation OK? | -- | Go to Step 11 | Go to Step 12 | ||||||||
11 | Replace the thermostat. Did you complete the repair? | -- | -- | |||||||||
12 | Reinstall the thermostat. Verify proper installation. Did you complete the repair? | -- | -- | |||||||||
13 | The outlet hose is hot and the inlet hose is warm.
Are the hoses installed in reverse? | -- | Go to Step 14 | Go to Step 15 | ||||||||
14 |
Does the condition persist? | -- | Go to Step 15 | |||||||||
15 |
Are both hoses warm? | -- | Go to Step 16 | Go to Step 17 | ||||||||
16 | Replace the heater core. Did you complete the repair? | -- | -- | |||||||||
17 | Is the inlet hose hot and the outlet hose warm? | -- | -- | |||||||||
18 | Inspect the connection on the temperature valve actuator. Is the temperature valve actuator connected? | -- | Go to Step 20 | Go to Step 19 | ||||||||
19 | Connect the temperature valve actuator. Verify proper operation of the system. Is the system operating properly? | -- | -- | |||||||||
20 | Inspect the following components:
Repair or replace the components as needed. Is the system operating properly? | -- | -- | |||||||||
21 | The airflow is low or nonexistent. Perform the HVAC functional inspection. Does the condition persist? | -- | Go to Step 22 | |||||||||
22 | Inspect the airflow out of the following outlets:
Is the airflow out of the defroster outlets or the vent outlets high? | -- | Go to Step 23 | Go to Step 24 | ||||||||
23 | Inspect for the following conditions:
Repair or replace the valves as needed. Did you complete the repair? | -- | -- | |||||||||
24 | The airflow out of the defroster outlets or the vent outlets is low or nonexistent.
Is the defroster airflow OK? | -- | Go to Step 25 | Go to Step 26 | ||||||||
25 |
Does the system operate properly? | -- | -- | |||||||||
26 | Inspect the blower speeds for airflow changes. Are the speed changes OK? | -- | Go to Step 27 | Go to Electrical Diagnosis | ||||||||
27 | Inspect the system for obstructions at the blower inlet and the plenum. Did you find any obstructions? | -- | Go to Step 28 | Go to Step 29 | ||||||||
28 | Remove the obstructions as needed. Does the system operate properly? | -- | -- | |||||||||
29 |
Did a change in the airflow occur? | -- | Go to Step 30 | Go to Step 31 | ||||||||
30 | Inspect the system for an obstruction between the blower and the system outlets. Remove any obstruction as needed. Does the system operate properly? | -- | -- | |||||||||
31 | Inspect the temperature valve and the actuator for proper operation. Repair the components as needed. Does the system operate properly? | -- | -- |
