Heating Performance Diagnostic
|
|
Heating Performance Diagnostic
|
|
Step
|
Action
|
Yes
|
No
|
|
DEFINITION: Heating system performance.
|
1
|
Were you sent here from Symptoms or another diagnostic table?
|
Go to
Step 2
|
Go to
Symptoms - HVAC Systems - Automatic
|
2
|
|
2.
|
Allow the engine to idle.
|
Does the engine reach a normal operating temperature?
|
Go to
Step 3
|
Go to
Step 9
|
3
|
|
2.
|
Select the minimum blower speed.
|
|
3.
|
Select the warmest temperature setting.
|
|
4.
|
Feel the temperature of the inlet and outlet heater hoses at the heater core.
|
Does the inlet heater hose feel warmer than the outlet heater hose?
|
Go to
Step 7
|
Go to
Step 4
|
4
|
|
1.
|
Install a thermometer into the center I/P PANEL air outlet.
|
|
2.
|
Secure a thermometer to the heater core outlet hose.
|
|
3.
|
Select the PANEL mode.
|
|
4.
|
Select the maximum blower speed.
|
|
5.
|
Select the warmest temperature setting.
|
|
6.
|
Record the temperature at the following locations:
|
|
|
•
|
The center I/P PANEL air outlet
|
|
|
•
|
The heater core outlet hose
|
|
7.
|
Compare the recorded temperatures.
|
Are the 2 temperature readings about equal?
|
Go to
Step 5
|
Go to
Step 6
|
5
|
|
1.
|
Inspect and repair the following areas of the vehicle for cold air leaks:
|
|
2.
|
Perform the necessary repairs.
|
Are the repairs complete?
|
Go to
Step 10
|
-
|
6
|
|
2.
|
Perform any necessary repairs.
|
Are the repairs complete?
|
Go to
Step 10
|
-
|
7
|
|
2.
|
Backflush the heater core.
|
|
4.
|
Select the FLOOR mode.
|
|
5.
|
Select the minimum blower speed.
|
|
6.
|
Select the warmest temperature setting.
|
|
7.
|
Feel the temperature of the inlet and outlet heater hoses at the heater core.
|
Does the inlet heater hose feel warmer than the outlet heater hose?
|
Go to
Step 8
|
Go to
Step 10
|
8
|
Replace the heater core. Refer to
Heater Core Replacement
.
Is the repair complete?
|
Go to
Step 10
|
-
|
9
|
Repair the low engine temperature concern. Refer to
Engine Fails To Reach Normal Operating Temperature
.
Is the repair complete?
|
Go to
Step 10
|
-
|
10
|
Operate the system in order to verify the repair.
Did you find and correct the condition?
|
System OK
|
Go to
Step 2
|
