John Deere CAB523631 – CAB: Recirculation Fan Power Circuit Open

The Cab Control Unit (CAB) has detected an open circuit in the electrical circuit that supplies power to the recirculation fan. This prevents the fan from receiving the necessary electrical power to operate, which directly affects the performance of the cab's heating, ventilation, and air conditioning (HVAC) system.

• 9450
• 9550
• 9650
• 9560 STS
• 9660 STS
• 9760 STS
• 9860 STS
• 9570 STS
• 9670 STS
• 9770 STS
• 9870 STS

1. 1

   Inspect the cab recirculation air filter for heavy plugging, which can strain the fan motor and lead to electrical issues.

2. 2

   Visually inspect the wiring harness leading to the recirculation fan motor for chafing, breaks, or loose connectors.

3. 3

   Check the recirculation fan circuit fuse (identified as fuse F10 in the engine compartment relay panel on 9660/9760 STS models).

4. 4

   Test the recirculation fan power relay (identified as K6 on 9450/9550/9650 models) by listening for a click when the fan is commanded on.

5. 5

   Check for battery voltage (12V or 24V) at the electrical connector of the recirculation fan motor with the ignition on and HVAC fan set to high.

6. 6

   Perform a resistance test on the unplugged fan motor. A reading of 'OL' or infinite resistance indicates an open circuit within the motor windings.

1. 1

   Disconnect power

   Disconnect the machine's battery before beginning any repair work for safety.

2. 2

   Access the recirculation fan

   Remove the necessary panels behind or under the operator's seat to access the recirculation fan located within the cab's HVAC housing. Refer to the operator's manual for specific panel removal instructions.

3. 3

   Repair wiring or replace electrical components

   If a blown fuse or faulty relay was identified during diagnostics, replace it with a component of the same rating. If wiring is damaged, repair the affected section using appropriate connectors and heat shrink for a sealed repair.

4. 4

   Replace recirculation fan motor

   If the motor failed the resistance test or receives voltage but does not run, disconnect its electrical connector, remove mounting hardware, and extract the assembly. Transfer the fan blade to the new motor if it is a separate component, install the new motor securely, and reconnect the electrical connector.

5. 5

   Reassemble and test

   Reinstall all panels, reconnect the battery, turn the ignition on, and test the recirculation fan at all speed settings. Verify the CAB523631 fault code has cleared from the diagnostic system.