AccuGrade GPS / Single UTS / Site and Laser Reference v11 for Excavators Electrical Power Supply (GPS Receiver) Caterpillar

System Operation Description:

There is no power to the GPS Receivers.

The following are possible causes:

• Display not turned on

• Fuse blown or Open Circuit Breaker

• Damaged harness or connector

• Failed receiver

• Power Jumper

• Power Module

Test Step 1. VERIFY THE DISPLAY WILL TURN ON.

1. Ensure the battery disconnect switch and the key start switch are in the ON position.

2. Turn the display ON.

Expected Result:

The display turns ON.

Results:

• OK - The display turns ON. Proceed to Test Step 2.

• NOT OK - The display does not turn ON.

  Repair: Perform the "Display Does Not Turn ON" procedure.

  STOP

Test Step 2. VERIFY THE GPS RECEIVERS POWER UP.

1. Verify that the power LED on the GPS receiver(s) is illuminated.

Expected Result:

All three of the light bars are illuminated.

Results:

• OK - The power LED on the GPS receiver(s) is illuminated.STOP

• NOT OK - The power LED on the GPS receiver(s) is not illuminated. Proceed to Test Step 3.

Test Step 3. CHECK THE POWER TO THE GPS RECEIVERS.

1. Disconnect the harness connectors from the GPS receiver connectors.

2. Measure the voltage between pin A and pin F on the harness connector for the receiver.

Expected Result:

The measured voltage is approximately machine voltage at each machine harness connector for each GPS receiver.

Results:

• OK - The measured voltage is approximately machine voltage at each machine harness connector for each GPS receiver. The GPS receiver has failed.

  Repair: Replace the failed GPS receiver.

  STOP

• NOT OK - The voltage is not approximately machine voltage at each machine harness connector for each GPS receiver. Proceed to Test Step 4.

Test Step 4. CHECK FUSE OR CIRCUIT BREAKER.

1. Check the fuse or circuit breaker.

   Note: Use the machine schematic in order to identify the correct fuse or circuit breaker.

Expected Result:

The fuse or the circuit breaker is OK.

Results:

• OK - The fuse or the circuit breaker is OK. Proceed to Test Step 5.

• NOT OK - The fuse or the circuit breaker has failed.

  Repair: Replace the fuse or the circuit breaker.

  STOP

Test Step 5. CHECK FOR AN OPEN POWER JUMPER IN THE POWER CIRCUIT IN THE HARNESS.

1. Use the AccuGrade electrical schematic for the machine in order to determine if a power jumper is used.

2. Place a jumper between pin B and pin C at the connector of the Display harness.

3. Turn the display ON.

Expected Result:

The GPS Receiver(s) power up.

Results:

• OK - The power jumper has failed.

  Repair: Replace the power jumper.

  STOP

• NOT OK - The GPS receiver(s) do not power up. The power jumper is not the cause of the failure. Proceed to Test Step 6.

Test Step 6. CHECK FOR A SHORTED POWER CIRCUIT IN THE HARNESS.

1. Check the Display harness for a short circuit condition.

   Note: Use the machine schematic to identify the power circuit wiring.

Expected Result:

There is no short circuit condition present in the harness.

Results:

• OK - There is no short circuit condition present in the harness. Proceed to Test Step 7.

• NOT OK - There is a short circuit condition present in the harness.

  Repair: Repair or replace the harness.

  STOP

Test Step 7. CHECK FOR AN OPEN POWER CIRCUIT IN THE HARNESS.

1. Check the Display harness for a open circuit condition.

   Note: Use the machine schematic to identify the power circuit wiring.

Expected Result:

There is no open circuit condition present in the harness.

Results:

• OK - There is no open circuit condition present in the harness. The power module (if equipped) has failed.

  Repair: Replace the power module.

  STOP

• NOT OK - There is an open circuit condition present in the harness.

  Repair: Repair or replace the harness.

  STOP