TD100 System Doesn’t Enable the Onboard Pump

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. This article guides you through the Finch II Display and pump control wiring. PTO and pump issues are beyond the scope of this article.

See the Figures below for details.
Figure 1 for voltage measurement locations.
Figure 2 for common pump control wiring.

Before checking the wiring, stand back and look at the TD100 system while it is turned on.

• Are there any error codes? Fix that first.
• Is the High-High or Spill alarm active? Resolve that first.
• Is the Finch II Display in Sleep Mode? Is it stuck in Sleep Mode? Fix that first.
• Is the Finch II Display dark? No lights or garbled display. Fix that first.
• Is the battery voltage to the Finch II Display below the nominal 12VDC? Fix that first.

Once the TD100 system is working normally, you can troubleshoot the loading pump problem from the Finch II Display out to the pump control solenoid (solenoid) if it is still an issue.

Troubleshooting Tools

Required Tools:

• Your eyes for visual inspection

Used as Needed:

• 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.

The Troubleshooting Steps

1. Verify that the solenoid wiring is securely connected to the Finch II Display RELAY2 NO and RELAY GND terminals.
   1. Correct the wiring if needed.
2. Visually inspect the wiring from the Finch II Display to the solenoid. You are looking for worn, cut or disconnected wires or signs of damage to the solenoid.
   1. Repair the damage if needed.
3. Measure the RELAY PWR voltage. It must be the normal battery voltage of about 12VDC. If no voltage, check the RELAY Power Fuse.
   1. If the fuse is OK, continue troubleshooting
   2. If the fuse is blown, replace it and continue troubleshooting. There is a reason why the fuse blew to protect the electrical circuit. You are looking 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.
4. Measure the voltage at the PUMP/AUX RELAY2 COM terminal. It must be the normal battery voltage of about 12VDC.
   1. If no voltage, check the PUMP Fuse. If the fuse is OK, continue troubleshooting.
   2. If the fuse is blown, replace it and continue troubleshooting. There is a reason why the fuse blew to protect the electrical circuit. You are looking for any place where the solenoid power wire is rubbing against the chassis, metal fittings or the ground wire.
   3. If the voltage is normal, continue troubleshooting.
5. Measure the voltage at the PUMP/AUX RELAY2 NO terminal. It must be the normal battery voltage of about 12VDC.
   1. 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.
   2. If no voltage at RELAY2 NO, the Finch II Display is defective.
6. Final test. This tests the pump control for the spill-prevention shutdown. 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?
   1. If yes, the Finch II Display is functioning normally.
   2. If no, the Finch II Display is defective.
      
      

Figure 1, Voltage Measurement Locations

The locations in Figure 1 are where the DMM probes are placed for voltage measurements inside the Finch II Display. Note that the terminals are filled with plugs and wiring. They have been removed from this drawing for clarity.

1. Black (-) probe on GND IN terminal. All internal Finch II Display voltage measurements are made with this circuit ground point.
2. 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.
3. 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.
4. 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.
5. 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.

Figure 2, Common Pump Control Wiring