New Holland NH 3053 – Engine Control Unit (ECU) / Engine Controller: LS Power stage cold start lamp - SOURCE HIGH

The voltage on the circuit is too high, which typically means there is an open circuit (such as a blown bulb or broken wire) or a short circuit to the battery (B+).

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1. 1

   Visually inspect the dash during cold conditions to see if the cold start lamp illuminates (a blown bulb causes an open circuit)

2. 2

   Test the wiring harness between the Engine ECU and the instrument cluster for an open circuit or a short to the battery

3. 3

   Inspect the pins at the Engine ECU and the back of the instrument cluster for corrosion, pushed-out pins, or loose connections

1. 1

   Turn off the ignition and disconnect the battery to prevent electrical damage.

   Ensure the machine is powered down before beginning electrical work.

2. 2

   Remove the instrument cluster panel to access the indicator bulbs.

   Gain access to the back of the dash panel.

3. 3

   Inspect the cold start lamp bulb. If the filament is broken (open circuit), replace the bulb.

   A blown bulb is a common cause for an open circuit fault.

4. 4

   If the bulb is intact, disconnect the wiring harness at both the instrument cluster and the Engine ECU.

   Prepare the harness for continuity and short testing.

5. 5

   Perform a continuity test on the specific wire controlling the cold start lamp. If there is a break in the wire, locate the damaged section and repair or splice the harness.

   Check for an open circuit in the wiring.

6. 6

   Test the wire for a short to a 12V power source. If voltage is present when it shouldn't be, isolate the short in the harness and repair it.

   Check for a short circuit to the battery (B+).

7. 7

   Reconnect all harnesses, ensuring the connectors are fully seated and locked.

   Secure all electrical connections.

8. 8

   Reconnect the battery, turn the key on, and use a diagnostic tool to clear the fault code. Cycle the key to verify the code does not return and the lamp functions normally.

   Verify the repair was successful.