Massey Ferguson 10.03.21 – AIRCON: Air Conditioning Compressor Relay Signal From AC Module Issue

The control module is detecting an improper signal, an open circuit, or a short in the electrical circuit that controls the air conditioning compressor 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

   Check the AC compressor fuse (often F30) for a blown condition, which can be caused by the low-pressure sensor grounding out.

2. 2

   Test the AC compressor relay (often K4) by swapping it with a known good relay of the same type.

3. 3

   Inspect the wiring harness and connectors between the AIRCON module and the relay block for chafed wires, corrosion, or loose pins.

4. 4

   Verify the AIRCON module is sending the correct voltage signal to the relay coil when the AC is commanded ON.

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical shorts during testing.

2. 2

   Access the Relay Panel

   Open the main fuse and relay box. Depending on your specific model, this is usually located on the right-hand console, under the steering cowl, or under the cab roof.

3. 3

   Remove and Replace the Relay

   Pull the AC compressor relay. If your diagnostic checks (or a bench test with a multimeter) proved the relay was faulty, install a new OEM replacement relay into the socket.

4. 4

   Repair Wiring

   If the relay was good but the signal wire was dead, trace the wire back to the AIRCON module. Repair any broken wires or clean corroded connector pins using electrical contact cleaner.

5. 5

   Reassemble and Test

   Reconnect the battery. Start the tractor and turn the AC on max. Verify that the compressor clutch engages and the air blows cold.

6. 6

   Clear Codes

   Use a diagnostic scan tool to clear the 10.03.21 fault code from the AIRCON module memory.