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GENERAL INFORMATION
tects the washer motor from system voltages
higher than 16 volts by automatically switching off
the high side circuit.
3.14.2 RELAY CONTROLS
Front wiper on relay
The front wiper switch is a direct input to the
BCM. The BCM sends a PCI Bus message to the
IPM informing it to turn on the front wiper on
relay. This relay is electronically controlled and
continuously monitored for malfunctions. The front
wiper on relay is turned on internally by the IPM
as soon as the IPM receives the message from the
BCM.
Front wiper high/low relay
The front wiper switch is a direct input to the
BCM. The BCM sends a PCI Bus message to the
IPM informing it to turn on the front wiper high/
low relay. The relay switches power between the
low speed and high speed windings of the wiper
motor. The front wiper high/low relay is turned on
internally by the IPM as soon as the IPM receives
the message from the BCM. This circuit is electron-
ically controlled and the coil side of the relay is
monitored for malfunctions.
Accessory relay
The accessory relay works in conjunction with the
IPM's power accessory delay feature to control the
operation of the radio, amplifier, EVIC, power
windows, washer motors, wiper motors, power sun-
roof, and power outlet. The accessory relay is
turned on through low side control internal to the
IPM as soon as the IPM receives information from
the BCM that the ignition is in the ACCY or RUN
position. This circuit is electronically controlled
and continuously monitored for malfunctions. De-
pending on the ignition switch position, the acces-
sory relay will remain on or will time-out and turn
off. The accessory relay remains on in the RUN and
ACCY positions of the ignition switch. In the OFF
position, the relay will remain energized for 45
seconds then turn off. During this time-out period,
if the driver or passenger doors are opened, the
relay will turn off immediately. While the ignition
switch is in the START position, the relay will also
drop-out, then resume operation. Accessory relay
operation is most noticeable by observing the oper-
ation of the radio.
Horn relay
The horn relay operates through a direct wire
input to the IPM from the horn switch or a PCI Bus
message from the BCM. The relay responds to the
horn switch, remote door lock and VTSS alarm
functions. The horn relay is powered through low
side control internal to the IPM. Under normal
operating conditions, if the horn is pressed for
longer than 30 seconds, the IPM will automatically
deactivate the horn to prevent damage to it. The
IPM will re-activate control of the relay after a 25
second cool-down period. This circuit is electroni-
cally controlled and continuously monitors the coil
side of the relay for malfunctions.
Front Blower & Rear Booster Fan relays
The front blower and the rear booster fan are
controlled by the Automatic Temperature Control
(ATC). When powered up, the ATC sends a relay on
request over the PCI Bus message to the IPM. The
front blower and rear booster fan relays are then
powered through low side controls internal to the
IPM. This circuit is electronically controlled and
continuously monitored for malfunctions.
Electronic Back Light (EBL) relay
The rear defogger switch is part of the Automatic
Temperature Control (ATC). When the ignition
switch is in the RUN position and the rear defogger
switch is turned on, the ATC sends a PCI Bus
message to the IPM. The EBL relay is then pow-
ered through low side control internal to the IPM.
The relay provides the power to the rear window
defogger grid, and ground is attached to the vehicle
body. The IPM will only allow the rear defogger to
operate in the RUN position. This circuit is elec-
tronically controlled and continuously monitors the
coil side of the relay for malfunctions.
Door Node Relay
The IPM energizes the door node relay when the
ignition switch is in Accessory, Run Start or Run
positions. The relay provides power to two 40 Amp
fuses. One for the Driver Door Module and the
other for the Passenger Door Module. When the
ignition is turned off, the IPM will continue to
energize the relay for 45 seconds or until one of the
doors is opened.
Starter Relay
The starter relay in the IPM receives battery
voltage through a hardwired input from the igni-
tion switch. The starter relay ground is controlled
by the PCM. When the relay is energized, the IPM
will provide battery voltage to the starter solenoid
through pin 5 of the C1 connector.
Run Relay
When the IPM receives information that the igni-
tion switch is in the run position, it will energize
the run only relay thus providing power to the rear
heated seats, climate control and the ABS.
Fuel Pump Relay
The PCM will provide the ground to energize the
coil of the fuel pump relay in the IPM when the
ignition switch is in the run or run start positions.
The IPM then provides power to the fuel pump.
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