Air Conditioning Clutch Relay Control Circuit
Table of contents
P0645 HUMMER Possible Causes
- Faulty Air Conditioning Clutch Relay
- Air Conditioning Clutch Relay harness is open or shorted
- Air Conditioning Clutch Relay circuit poor electrical connection
- Faulty Powertrain Control Module (PCM)
How do I fix code P0645 HUMMER?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Cost of diagnosing the P0645 HUMMER code
The cost of diagnosing the P0645 HUMMER code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P0645 HUMMER Description
Battery positive voltage is supplied to the A/C compressor clutch relay. The Powertrain Control Module (PCM) controls the relay by grounding the control circuit through an internal solid-state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component on, the voltage of the control circuit should be near 0 volts. When the PCM is commanding the control circuit to a component off, the voltage potential of the circuit should be near battery voltage. If the fault detection circuit senses a voltage other than what is expected, this Diagnostic Trouble Code (DTC) will set.
