Massey Ferguson 10.02.22 – AC Module (AIRCON): Optional Cab Heater Pump Relay Signal From AC Module (AIRCON)

The Air Conditioning (AIRCON) control module is detecting an abnormal electrical condition—such as an open circuit, short to ground, or short to power—on the signal circuit that controls the optional cab heater water pump relay.

• 7724S
• 5712SL
• 7722
• 7722S
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Inspect the cab fuse box for any blown fuses related to the HVAC system, cab heater, or auxiliary water pump.

2. 2

   Locate the Optional Cab Heater Pump Relay in the cab electrical panel and swap it with a known good relay of the same type (e.g., a standard 12V 40A or 5-pin relay) to see if the fault clears.

3. 3

   Inspect the wiring harness between the AC Module and the relay block for chafed wires, corrosion at the connector pins, or loose grounds.

4. 4

   Use a multimeter to verify continuity on the signal wire from the AC Module to the relay socket, and verify that the relay is receiving proper 12V power and ground.

1. 1

   Disconnect Power

   Turn off the tractor ignition and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Access the Relay Panel

   Open the cab fuse/relay access panel (location varies by series, typically on the right-hand console or behind the seat).

3. 3

   Replace the Relay

   If the diagnostic checks point to a failed relay coil, remove the faulty Optional Cab Heater Pump Relay and install a new OEM 12V relay.

4. 4

   Repair Wiring (If Applicable)

   If the relay is functional but the signal wire is broken or shorted, repair the damaged section of the wiring harness using heat-shrink butt connectors. Ensure the harness is secured away from sharp edges.

5. 5

   Module Replacement (Worst Case)

   If the wiring is intact and the relay is good, but the AC Module is failing to send the signal, the AC control panel/module itself may need to be replaced.

6. 6

   Clear Codes

   Reconnect the battery, turn the ignition on, and use a diagnostic scan tool to clear the 10.02.22 fault code. Test the cab heater to ensure the auxiliary pump engages.