F 250 4WD Pickup V8-7.3L DSL Turbo VIN K (1994)
Fuel Heater: Testing and Inspection
FUEL HEATER CIRCUIT TEST
1. Disconnect the fuel heater lead on the fuel filter. The heater lead is located on top of the filter housing, diagonally opposite the fuel filter schrader
valve.
2. Connect one test lamp lead to the fuel heater wiring connector and the other lead to ground.
3. Turn the ignition switch on and check for operation of the test lamp.
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If the test lamp is on, the power supply circuit is complete.
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If the test lamp is off, check the fusible link.
- If the link is good repair the affected wiring.
- If the link is bad, repair and verify operation of the heater.
FUEL HEATER OPERATION TEST
1. Disconnect the fuel heater lead on the fuel filter.
2. Connect one test lamp lead to the fuel heater wiring connector and the other lead to the heater terminal.
3. Turn the ignition switch on.
4. If fuel temperature is above 0°C (30°F) apply freeze spray (available at most electronic supply stores) to the fuel filter header.
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The test lamp should turn on within 10 minutes of applying the freeze spray. If it does not, replace the fuel heater.
NOTE: A heavy application of freeze spray must be applied to the header to properly perform this test. A thick layer of frost accumulation is
necessary to ensure proper cooling of the fuel.
CAUTION: Wear safety glasses and gloves when using freeze spray. Avoid contact with skin or eyes to prevent freeze injuries.
