Wired Remote Signal Test - Y1 / Y2 / Y3

This procedure checks the remote controller supply voltage and communication signal integrity on systems using Y1, Y2 and Y3 terminals.

Quick Answer
  • Y1 to Y3: approximately 12 V DC
  • Minimum acceptable Y1-Y3 voltage: 11.4 V DC
  • Communication pulse signal: approximately 7-12 V DC pulsing

What This Test Checks

The test confirms:

  • Remote controller DC supply is present.
  • The Y1-Y3 supply voltage is within the acceptable range.
  • A communication pulse is present on the Y2 circuit.
  • The wiring between the remote controller and indoor unit is intact.

Y1 Y2 Y3 wired remote terminal reference

Tools Required

  • Digital multimeter set to DC voltage

Test Procedure

  1. Measure voltage between Y1 and Y3.
  2. Confirm the reading is approximately 12 V DC and not below 11.4 V DC.
  3. Disconnect the Y2 conductor.
  4. Measure between Y3 and the disconnected Y2 cable going toward the indoor unit.
  5. Measure between Y3 and the Y2 terminal.
  6. Check for a pulsing DC signal in the approximate range of 7-12 V DC.

Y1 Y2 Y3 wired remote signal test reference

Y2 disconnected signal test reference

Wired remote pulse signal measurement reference

Pass Criteria

TestPass Criteria
Y1-Y3 supply voltage≥ 11.4 V DC, nominally around 12 V DC
Y2 communication signalPulsing signal approximately 7-12 V DC

If the Test Fails

Y1-Y3 below 11.4 V DC or 0 V
Check wiring continuity and connections. If the wiring is correct, investigate the controller PCB / supply circuit.
No pulse signal present
Repair the wiring between the remote controller and indoor unit, then repeat the applicable System Signal Test - Indoor to Outdoor.

Technician Checklist

  1. Confirm the system uses Y1/Y2/Y3 wired remote terminals.
  2. Set the multimeter to DC voltage.
  3. Confirm Y1-Y3 is at least 11.4 V DC.
  4. Disconnect Y2 as shown in the procedure.
  5. Check both sides of the Y2 circuit relative to Y3.
  6. Confirm a 7-12 V DC pulse is present.
  7. If voltage is low or absent, check wiring and supply PCB.
  8. If the pulse is absent, repair the communication wiring and retest.