Remove the connector from the fuel heater.
• Rear gear train
• Front gear train.
Check for proper voltage to the fuel heater at the OEM connector.
Fuel heater voltage: 12-VDC
If the voltage is not within specifications, refer to the OEM service manual.
Measure the resistance across the two connector pins on the fuel heater connector.
NOTE: Resistance at the connector pins will be zero if the temperature is above the range needed to turn on the
thermostat. It will be necessary to place ice around the fuel heater to bring the temperature down to activation point
of the thermostat.
• Front gear train operating range is 0.3 to 0.45 Ohms.
• Rear gear train operating range is 0.43 to 0.53 Ohms.
If resistance is out if range, replace the fuel heater assembly.
