New Holland 3659 – EDC: Battery Voltage Exceeds Normal Range

The Engine Control Module (ECM) has detected that the battery supply voltage is above the normal operating range (typically exceeding 14.7V to 15V). This overcharging condition is a critical fault that can cause severe damage to sensitive electronic components. As a protective measure, the system may disable the power stage diagnosis to prevent further electrical damage.

• T4
• T5
• T7
• T8
• Boomer
• Haytools
• Windrowers
• TN95FA
• TM Series
• TS-A Series
• 8670
• 8770
• 8870
• 8970
• 10 Series
• 30 Series
• 2008 Industrial models

1. 1

   Inspect battery and connections: Ensure terminals are clean, tight, and free of corrosion. Check the main chassis ground strap for a secure, clean connection.

2. 2

   Perform a static battery voltage test: With the engine OFF, measure voltage at the battery terminals (should be approximately 12.6V).

3. 3

   Perform a charging system voltage test: With the engine running at approximately 1500 RPM, measure battery voltage. A reading significantly above 14.7V (especially over 15V) indicates an overcharging condition, strongly suggesting a faulty voltage regulator.

4. 4

   Perform a voltage drop test: Measure voltage between the alternator's main output post (B+) and the positive battery terminal with the engine running. A reading higher than 0.5V indicates high resistance in the wiring or connections.

5. 5

   Perform an AC ripple test: Set a multimeter to AC volts and measure at the battery terminals with the engine running. A reading over 50-100 millivolts (0.05-0.10V AC) indicates a failing diode in the alternator's rectifier.

1. 1

   Safety First

   Disconnect the negative battery terminal to prevent accidental short circuits.

2. 2

   Access the Alternator

   Depending on the machine model, this may require removing engine covers or other components.

3. 3

   Loosen Belt Tension

   Loosen the alternator drive belt by releasing the tensioner. Remove the belt from the alternator pulley.

4. 4

   Disconnect Electrical Connections

   Disconnect the main battery cable (B+ terminal) and the smaller electrical connector(s) from the back of the alternator. It is good practice to label the wires if there are multiple.

5. 5

   Remove the Alternator

   Remove the mounting bolts that secure the alternator to the engine bracket and remove the old alternator.

6. 6

   Install the New Alternator

   Mount the new alternator and tighten the mounting bolts to the manufacturer's specified torque.

7. 7

   Reconnect and Tension Belt

   Reinstall the drive belt and apply the correct tension as per the machine's service manual.

8. 8

   Reconnect Electrical and Battery

   Reattach the electrical connectors and the main power cable to the new alternator. Finally, reconnect the negative battery terminal.

9. 9

   Verify the Repair

   Start the engine and repeat the 'Charging System Voltage Test.' The voltage should now read within the normal range (13.5-14.5 volts).