Circuit Description
This symptom chart will aid in diagnosing a failed Power Take-Off (PTO) indicator. This diagnostic assumes that the PTO solenoid is functional and only the indicator is failing to come on. When the ignition switch is in RUN, voltage should be present on the Ignition 1 Voltage circuit. When the PTO switch is turned to ON, the LED will illuminate. The indicator has its own ground circuit. The PTO enable switch indicator and PTO solenoid have different ground circuits. Therefore, the indicator may be illuminated when the PTO solenoid is disengaged.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Power Take-Off (PTO) Schematics | |||
1 | Did you review the Power Take-Off Description and Operation and perform the necessary inspections? | Go to Step 2 | |
2 | Verify the fault is present. Does the system operate normally? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 | Does the PTO solenoid engage? | Go to Step 4 | |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 6 | |
Do you have continuity? | Go to Step 8 | Go to Step 7 | |
6 | Repair the open or high resistance in both PTO On Switch Signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
7 | Repair the open or high resistance in the ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
8 | Replace the PTO Enable switch. Refer to Upfitters instructions. Did you complete the replacement? | Go to Step 9 | -- |
9 | Test drive the vehicle and operate the PTO system as described in the supporting test. Does the symptom occur? | Go to Step 3 | System OK |
