Silverado 1500 2WD V8-4.8L VIN V (2006)
Ignition Relay: Testing and Inspection
IGNITION RELAY DIAGNOSIS
CIRCUIT DESCRIPTION
The ignition relay is a normally open relay. The relay armature is held in the open position by spring tension. When the ignition switch is turned to the
run or start position, current will flow through the relay coil. A wire connected to the other end of the relay coil completes the path to ground. The
electromagnetic field created by the relay coil, overcomes the spring tension and moves the armature allowing the relay contacts to close. The closed
relay contacts allow current to flow from the battery to the following fuses:
-
The PCM 1 fuse
-
The ETC/ECM fuse
-
The INJ 1 fuse
-
The INJ 2 fuse
-
The SBA fuse, if equipped.
When the ignition switch is turned to the OFF position, the electromagnetic field collapses. This action allows the spring tension to move the armature
away from the relay contacts, which interrupts current flow to the fuses.
If the ignition relay fails to close, the engine will crank, but will not run. The class 2 communications will be available with the use of a scan tool.
The ignition relay table assumes that the vehicle battery is fully charged. Refer to Battery Inspection/Test (Non-HP2) Battery Inspection/Test (HP2) in
Starting and Charging. See: Starting and Charging/Testing and Inspection/Component Tests and General Diagnostics/Battery Inspection/Test
TEST
