SENSOR GP-POS 1618946 - Caterpillar

Operation Description:There are several reasons why no power is supplied to the display. The following list provides several possible causes.
Master power switch or ignition switch are in the off position
Blown fuse
Wiring problem
Damaged harness or display connector
Unserviceable displayUse the following procedures in order to determine the source of the problem of no power to the display.Test Step 1. There is no power to the display.
Ensure that the disconnect switch and the ignition switch are turned to the ON position.
Turn on the display. If the display turns on, stop.
If the display does not turn on, the AccuGrade system fuse may be blown. Check the fuse.Expected Result:The fuse is OK.Results:
OK - The fuse is OK. Proceed to Test Step 2.
NOT OK - The fuse is NOT OK. Proceed to Test Step 3.Test Step 2. Check for voltage at the display.Disconnect the harness connector that is connected to the back of the display. Measure the voltage between pin D and pin F.Expected Result:The measured voltage is approximately equal to the system voltage.Results:
OK - The measured voltage is approximately equal to the system voltage. Proceed to Step 6.
NOT OK - The measured voltage is not system voltage. If the display still does not operate properly, then proceed to Step 3.Test Step 3. Check the display harness for a short circuit.Remove the harness connector from the back of the display. Measure the resistance between pin D and pin F. Measure the resistance between pin D and ground. Measure the resistance between pin F and ground.Expected Result:The resistance should check D to F? D to ground? F to ground? ????? infinite ohms.Results:
OK - The resistance checks ????? infinite ohms. Proceed to Step 4.
Not OK - The resistance shows that the circuit is shorted.Repair: Repair or replace the display harness. Replace the AccuGrade system fuse. Check to see if the display will power up. If the display still does not operate properly, then proceed to Step 4.Test Step 4. Check the display harness for an open circuit.Remove the harness connector from the back of the display. Measure the resistance between pin D and pin F. Measure the resistance between pin D and ground. Measure the resistance between pin F and ground.Expected Result:The resistance should check D to F? D to ground? F to ground? ????? infinite ohms.Results:
OK - The resistance checks ????? infinite ohms. Proceed to Step 5.
Not OK - The resistance shows that the circuit is open.Repair: Repair or replace the display harness. Replace the AccuGrade system fuse. Check to see if the display will power up. If the display still does not operate properly, then proceed to Step 6.Test Step 5. Check the terminator resistors.
Turn the key start switch and the main disconnect switch for the machine to the off position.
Turn the key start switch and the main disconnect switch for the machine to the off position.
Turn the key start switch and the main disconnect switch for the machine to the off position.The measure resistance of each resistor should be 120 12 ohms.Expected