Onboard Pump Not Working
Troubleshoot an in-service failure of the TD100 system and the onboard loading pump control, from initial diagnostics to solenoid wiring.
Diagnostics
Initial Checks
This troubleshooting guidance is for an in-service failure of the TD100 system and the onboard loading pump control. The loading pump was working well and then it quit pumping.
Before checking the wiring, look at the TD100 system while it is turned on.
- Are there any error codes?
- Is the High-High or Spill alarm active?
- Is the FINCH II Display in Sleep Mode? Is it stuck in Sleep Mode?
- Is the FINCH II Display dark? No lights or garbled display.
- Is the battery voltage to the FINCH II Display below the nominal 12VDC?
Once the TD100 system is working normally, you can troubleshoot the loading pump problem from the FINCH II to the pump control solenoid if it is still an issue.
Equipment
Troubleshooting Tools
- Digital Multimeter (DMM) to measure the voltage.
- Electrical test light to indicate the presence and stability of the voltage.
- Bright flashlight or work light to inspect the wiring and connections.
Procedure
Troubleshooting Steps
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1
Inspect the Wiring
Visually inspect the wiring from the FINCH II to the solenoid. You are looking for worn, cut or disconnected wires or signs of damage to the solenoid. Repair the damage if needed.
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2
Verify Solenoid Connections
Verify the solenoid wiring is securely connected to the FINCH II RELAY2 NO and RELAY GND terminals. Correct the wiring if needed.
Note
If the fuse was replaced, continue troubleshooting. There is a reason why the fuse blew to protect the electrical circuit. Look for any place where the solenoid power wire is rubbing against the chassis, metal fittings, or the ground wire. Check the PUMP Fuse — it may be blown along with the RELAY POWER Fuse.
Reference
Voltage Measurement Locations
The locations below show where the DMM probes are placed for voltage measurements inside the FINCH II. Note that the terminals are filled with plugs and wiring — they have been removed from this drawing for clarity.
- Black (−) probe on GND IN terminal. All internal FINCH II Display voltage measurements are made with this circuit ground point.
- Red (+) probe on the PWR IN terminal to measure the voltage into the display from the vehicle's battery power system. It must be close to the normal battery voltage of 12VDC.
- Red (+) probe on the RELAY PWR terminal to measure voltage to the solenoid. It must be the same as the voltage at the PWR IN terminal. Measure the RELAY PWR voltage — it must be the normal battery voltage of about 12VDC. If no voltage, check the RELAY Power Fuse. If the fuse is OK, continue troubleshooting.
- Red (+) probe on the RELAY2 COM terminal to measure voltage to the solenoid. It must be the same as the voltage at the PWR IN terminal. Measure the voltage at the PUMP RELAY2 COM terminal — it must be the normal battery voltage of about 12VDC. If no voltage, check the PUMP Fuse. If the fuse is OK, and the voltage is normal, continue troubleshooting.
- Red (+) probe on the RELAY2 NO terminal to measure voltage to the solenoid. It must be the same as the voltage at the PWR IN terminal. Measure the voltage at the PUMP RELAY2 NO terminal — it must be the normal battery voltage of about 12VDC.
- If the voltage is correct, confirm that the wires to the pump control solenoid are connected to RELAY2 NO and RELAY GND. Continue to troubleshoot the solenoid and wiring external to the TD100 system.
- If no voltage at RELAY2 NO, the FINCH II Display is defective.
Press the PUMP RELAY TEST button several times while measuring the voltage at RELAY2 NO. Does the voltage drop to 0VDC while pressed and back up to about 12VDC when released?
- If yes, the FINCH II Display is functioning normally.
- If no, the FINCH II Display is defective.
Reference
Common Pump Control Wiring
