For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Engine Cooling Diagnostic System Check? | Go to Step 2 | Go to Cooling Fan System Check
2 | Turn ON the ignition with the engine OFF. Does the heater auxiliary water pump operate? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3
3 | Disconnect the heater auxiliary water pump connector. With a test lamp connected to a good ground, probe circuit X70 at the heater auxiliary water pump connector. Does the test lamp illuminate? | Go to Step 4 | Go to Step 5
4 | Connect a test lamp between circuit X70 and circuit F75 at the heater auxiliary water pump connector. Does the test lamp illuminate? | Go to Step 7 | Go to Step 6
5 | Repair circuit X70, X68, X67 or X868 for an open, high resistance or short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | --
6 | Repair circuit F75 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | --
7 | Inspect for poor connections at the heater auxiliary water pump connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 9 | Go to Step 8
8 | Replace the heater water auxiliary pump. Refer to Heater Water Auxiliary Pump Replacement . Is the repair complete? | Go to Step 9 | --
9 | Operate the system in order to verify the repair? Did you correct the condition? | System OK | Go to Step 2