KF18 - Check HFC Power-to-Fan Circuit Continuity

- Key "OFF".

- Breakout box installed, Powertrain Control Module (PCM) disconnected.

- Low Fan Control (LFC) relay disconnected.

- Cooling fan disconnected.

- Disconnect High Fan Control (HFC) relay.

- Measure resistance between the HFC Power-To-Fan output pin at the HFC vehicle harness connector and the HFC Power-To-Fan input pin at the cooling fan vehicle harness connector.

- Is resistance less than 5.0 ohms?

Yes -- Replace HFC relay. Remove breakout box. Reconnect all components. Re-evaluate symptom.

No -- Service open circuit. Remove breakout box. Reconnect all components. Re-evaluate symptom.