C 2500 Truck 2WD V8-6.6L DSL Turbo VIN 1 (2001)
Ignition Relay: Testing and Inspection
IGNITION RELAY DIAGNOSIS
CIRCUIT DESCRIPTION
The ignition relay supplies ignition voltage to the following components:
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The glow plugs
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The Fuel Injection Control Module (FICM)
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The Engine Control Module (ECM)
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The fuel pressure regulator
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The Mass Air Flow (MAF) sensor
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The fuel heater
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The A/C compressor relay
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The daytime running lamps
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The rear defogger
DIAGNOSTIC AIDS
If the IGN relay fails open:
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The scan data WILL be available.
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The vehicle WILL crank no start.
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The dash indicator lights WILL illuminate.
TEST DESCRIPTION
Steps 1-8