INSTALLATION
NOTE: Replacement of the PTFE thread sealing
tape is required anytime the rear A/C low pressure
switch is removed from the rear suction line line.
Failure to replace the sealing tape could result in a
rear refrigerant system leak.
(1) Remove the tape or plug from the rear suction
line fitting.
(2) Install PTFE thread sealing tape onto the rear
A/C low pressure switch and install the switch onto
the rear suction line. Tightened the A/C low pressure
switch to 10 N´m (88 in. lbs.).
(3) Connect the wiring harness connector to the
rear A/C low pressure switch.
(4) Install new insulating tape around the rear A/C
low pressure switch area.
(5) Reconnect the negative battery cable.
(6) Evacuate the rear refrigerant system (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING
- STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE).
(7) Charge the rear refrigerant system (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE).
(8) Install the cover onto the rear A/C evaporator
housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C EVAPORA-
TOR COVER-REAR - INSTALLATION).
BLOWER MOTOR RELAY
DESCRIPTION
The three rear blower motor relays used for the
rear A/C system are International Standards Organi-
zation (ISO)-type relays (Fig. 11). Relays conforming
to the ISO specifications have common physical
dimensions, current capacities, terminal functions
and patterns. The rear blower motor relays are elec-
tromechanical devices that switches fused battery
current directly to the rear blower motors. The rear
blower motor relays are energized when the relay
coils are provided battery current by the rear blower
motor switch (Refer to 24 - HEATING & AIR CON-
DITIONING/CONTROLS/BLOWER MOTOR
SWITCH - DESCRIPTION).
The rear blower motor relays are located in the
relay block in the rear A/C evaporator housing.
OPERATION
The three ISO-standard rear blower motor relays
are electromechanical switches that uses a low cur-
rent input from the rear blower motor switch to con-
trol the high current output to the rear blower
motors. The movable, common feed relay contact is
held against the fixed, normally closed relay contact
by spring pressure. When the electromagnetic relay
coil is energized, it draws the movable common feed
relay contact away from the fixed, normally closed
relay contact and, holds it against the fixed, normally
open relay contact. This action allows high current to
flow to the rear blower motors.
When the relay coil is de-energized, spring pres-
sure returns the movable relay contact back against
the fixed, normally closed contact point. The resistor
Fig. 10 Rear A/C Low Pressure Switch
1 - INSULATING TAPE
2 - REAR A/C EVAPORATOR HOUSING
3 - WIRE HARNESS CONNECTOR
4 - REAR A/C LOW PRESSURE SWITCH
5 - REAR SUCTION LINE FITTING
Fig. 11 Rear Blower Motor Relays
1 - STANDARD ISO RELAY
2 - TERMINAL PATTERN
VACONTROLS - REAR 24 - 33
