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

System Operation Description:

The data radio is not receiving power.

The probable conditions that cause this symptom are in the following list:

• Display is not turned "ON".

• A fuse is open or a circuit breaker is open.

• Failed data radio

• Power Jumper

• Power Module

• Damaged harness or connector

Test Step 1. VERIFY THAT THE DISPLAY WILL TURN ON.

1. Ensure that 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: Refer to the Troubleshooting section of Service Manual, KENR8980, "Electrical Power Supply (Display)".

  STOP

Test Step 2. VERIFY THAT THE DATA RADIO POWERS UP.

1. Verify that the power LED on the data radio is illuminated.

Expected Result:

The power LED on the data radio is illuminated.

Results:

• OK - The power LED on the data radio is illuminated.

  Repair: The cause of the problem was Display. The Display was turned Off. Return the machine to service.

  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 connector for the data radio.

2. Measure the voltage between pin 1 and pin 2 on the harness connector for the data radio.

Expected Result:

The measured voltage is approximately machine voltage.

Results:

• OK - The measured voltage is approximately machine voltage.

  Repair: The data radio has failed. Replace the failed AccuGrade radio.

  STOP

• NOT OK - The voltage is not approximately machine voltage. Proceed to Test Step 4.

Test Step 4. CHECK FUSE OR CIRCUIT BREAKER.

1. Check the fuse or the circuit breaker.

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

Expected Result:

The fuse or the circuit breaker is okay.

Results:

• OK - The fuse or the circuit breaker is okay. 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 electrical schematic for the machine in order to determine if a power jumper is used.

2. Disconnect the power jumper.

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

4. Turn the Display ON.

Expected Result:

The data radio powers up.

Results:

• OK - The power jumper has failed.

  Repair: Replace the power jumper.

  STOP

• NOT OK - The data radio does 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 harness for the Display for a short circuit condition.

   Note: Use the schematic for your machine in order to identify the wiring for the power circuit.

Expected Result:

A short circuit condition is not present in the harness.

Results:

• OK - A short circuit condition is not present in the harness. Proceed to Test Step 7.

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

  Repair: Repair the harness or replace the harness.

  STOP

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

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

   Note: Use the schematic for your machine in order to identify the wiring for the power circuit.

Expected Result:

An open circuit condition is not present in the harness.

Results:

• OK - An open circuit condition is not present in the harness. The power module (if equipped) has failed.

  Repair: Replace the power module.

  STOP

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

  Repair: Repair the harness or replace the harness.

  STOP