John Deere 3320 Warning Lights and Symbols (Meaning and Fixes)

Quick answer: These dashboard warning lights follow the ISO 2575 international standard. A red symbol means stop the machine and check immediately, amber or yellow means service soon, and green or blue symbols are normal status indicators. Each symbol below is explained with its meaning, the most likely cause, and the recommended action.

The John Deere 3320 compact utility tractor's instrument cluster provides essential warnings for safe operation. Understanding these indicators helps prevent damage and ensures longevity, especially during heavy PTO or loader work.

How to read the colors: Red indicators require immediate shutdown, amber indicates caution or service needed, green/blue are for active functions like PTO or high beam.

John Deere 3320 Warning Light Symbols

SymbolNameColorWhat it meansWhat to do
Master Warning (Stop)REDThis red stop light signals a critical fault that requires stopping the engine immediately to prevent severe damage to the 3320's drivetrain or engine.Stop the tractor and check the LCD display for the specific fault code.
Master CautionAMBERThe amber caution light alerts you to a non-critical issue that needs attention soon, such as a service reminder or low fluid level.Check the instrument panel messages and address the indicated system.
Check Engine (MIL)AMBERThis light indicates an engine management or emission system fault, often related to the 3320's Yanmar diesel engine sensors.Have the engine diagnosed by a John Deere dealer using diagnostic software.
Engine Oil PressureREDLow engine oil pressure light illuminates when pressure drops below safe levels, risking bearing damage in the 3320's engine.Stop immediately and check engine oil level and pressure sender.
Battery / ChargingREDThe battery light indicates the alternator is not charging or the battery voltage is low on your 3320.Check alternator belt tension and battery connections.
Coolant TemperatureREDEngine coolant temperature is too high; risk of overheating the 3320's engine during heavy mowing or tillage.Stop engine and allow to cool; clean radiator fins if needed.
ATTransmission TempAMBERHydrostatic or eHydro transmission oil temperature is elevated; reduce load to avoid overheating the 3320's drive system.Reduce ground speed or shift to a higher range to let transmission cool.
PParking BrakeAMBERParking brake is engaged on your 3320; it will not move until released.Release the parking brake before operating.
Glow Plug / PreheatAMBERGlow plugs are active for cold starting the 3320's diesel engine; wait until the light goes out to start.Turn key to the preheat position and wait for the indicator to extinguish.
Low FuelAMBERFuel level is low in the 3320's tank; refuel soon to avoid air in the fuel system.Add diesel fuel.
High BeamBLUEHigh beam headlights are on for improved visibility during night operation of the 3320.Dim when approaching other vehicles.
PTOPTO EngagedGREENRear PTO is engaged on your 3320, powering implements like mowers or tillers.Disengage PTO when not in use to prevent accidental starts.
Differential LockAMBERDifferential lock is engaged to maximize traction on the 3320 in slippery conditions.Disengage diff lock when turning on hard surfaces to avoid driveline bind.
Water in FuelAMBERWater detected in the fuel/water separator; drain immediately to protect the 3320's injection system.Drain water from the separator bowl located on the frame.

14 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.

Most Important Warning Lights

Engine Overheating

Common causes

  • Clogged radiator screen
  • Low coolant level
  • Failed thermostat

What to do

Stop the 3320 immediately, allow engine to cool, then clean the radiator screen and check coolant level in the overflow bottle.

Low Engine Oil Pressure

Common causes

  • Low oil level
  • Oil filter clogged
  • Oil pump failure

What to do

Shut off engine, check oil level with dipstick, and add John Deere Plus-50 oil if low. If light persists, consult dealer.

Transmission Overheating

Common causes

  • Continuous heavy load
  • Low transmission fluid
  • Clogged cooler fins

What to do

Reduce load and shift to a lower range. If light stays on, check transmission fluid level and clean the external cooler fins on the 3320.

Charging System Failure

Common causes

  • Loose alternator belt
  • Failed alternator
  • Corroded battery terminals

What to do

Check alternator belt tension (should deflect 1/2 inch) and clean battery terminals. Replace alternator if necessary.

Fuel System Contamination

Common causes

  • Water in fuel
  • Clogged fuel filter
  • Bad fuel

What to do

Drain water from the fuel filter/water separator (located on left side of engine) and replace the fuel filter if the light remains on.

Frequently Asked Questions

Why does my John Deere 3320's check engine light come on after refueling?

If the fuel cap is not tightened fully, the evaporative system may detect a leak. Also, using low-quality diesel can trigger the light. Tighten the cap and cycle the key; if it persists, have the fuel quality checked.

What does the flashing amber light on the dash mean?

A flashing amber caution light on the 3320 typically indicates a transmission temperature warning or a hydraulic system pressure issue. Check the LCD for specific fault codes and reduce load accordingly.

How long should I wait after the glow plug light goes out before starting?

On the 3320, start the engine immediately after the glow plug light extinguishes. Waiting too long may cause hard starting in cold weather.

Can I continue working if the transmission temp light is on but not flashing?

No, if the transmission temp light is steady amber, reduce load immediately. If it stays on, stop and let the transmission cool. Continuing may cause damage to the eHydro transmission.

What is the service hour meter light on my 3320?

The wrench icon illuminates at 50-hour intervals to remind you of scheduled maintenance, such as engine oil and filter changes. Reset it after service by following the procedure in the owner's manual.

Why does my parking brake light not go off even when released?

This could indicate a faulty parking brake switch on the 3320. Check the lever position; if the light remains, the switch may need adjustment or replacement at a dealer.