Envoy 2WD V8-5.3L VIN P (2004)
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 pulls the armature contact into the stationary contact of the relay load
circuit. The closed relay contacts allows current to flow from the battery to the following fuses:
-
ETC
-
INJ A
-
INJ B
When the ignition switch is turned to the OFF position, the electromagnetic field collapses. This action allows the spring tension to move the armature
contact away from the relay load circuit 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.
TEST
Steps 1-4
