TM 9-2320-361-34 17-20. FUEL BURNING PERSONNEL HEATER TESTING (Contd) KEY TO TEST SCHEMATIC 1. Electric fuel pump 7. Power source lead 2. Fuel tubing 8. 24-volt DC power source 3. Fuel filter 9. Multimeter 4. Fuel flowmeter 10. Wiring harness 5. Fuel shutoff valve 11. Control box 6. Heater assembly 12. Fuel tank 17-57