Water pump fuse keeps blowing
2020 travel trailer, 12V diaphragm water pump. 30A shore, converter on
Customer says: The water pump blows its fuse every time we turn it on. We've gone through five fuses.
A 15 A fuse is in the pump slot, which matches the panel label.
Tests you can run
- New fuse, pump switch on, watch it
- Unplug the pump, new fuse, switch on
- Pump unplugged: ohms from the pump's positive lead to chassis ground
- Ohms across the pump motor terminals
- Run the pump on a bench supply
- Trace the positive wire from the pump back toward the panel
- Put in a 30 A fuse to get it running
- Replace the pump
Repair options
The lesson behind this case
Keep going on 12V and batteries
Learn it
- Volts, amps and ohms, the simple way
- Voltage drop: the test that finds bad grounds
- Practice: find the bad connection
- Batteries: lead-acid vs lithium
- Fuses, breakers and grounds
Prove it
- Back lights are dim
- Battery dies even on shore power
- Lithium won't charge on cold mornings
- Coach is dead, battery is fine
- Batteries dead after storage