Part 3 of 3
FRONT WIPER/WASHER SWITCHThe front wiper and washer switches are integral to the right (wiper) control stalk of the multi-function switch.
Fig.16 Washer Fluid Level Switch:
WASHER FLUID LEVEL SWITCH
The washer fluid level switch is a single pole, single throw reed-type switch mounted at the rear of the sump area near the bottom of the washer reservoir. Only the molded plastic switch mounting flange and the integral connector receptacle are visible when the switch is installed in the reservoir. A short nipple formation extends from the inner surface of the switch mounting flange, and a barb on the nipple near the switch mounting flange is pressed through a rubber grommet seal installed in the mounting hole of the reservoir. A small, molded plastic float has two pivot pins near its center that are snapped into two receptacles near the ends of two stanchions that extend toward the float from the switch nipple formation. A small magnet is secured within the end of the float nearest the switch nipple formation, and a reed switch is concealed within the nipple. A diagnostic resistor is connected between the two switch terminals within the switch mounting flange. The washer fluid level switch cannot be adjusted or repaired. If faulty or damaged, the switch must be replaced.
The washer fluid level switch uses a pivoting, oblong float to monitor the level of the washer fluid in the washer reservoir. The float contains a small magnet. When the float pivots, the proximity of this magnet to a stationary reed switch within the nipple formation of the switch changes. When the fluid level in the washer reservoir is at or above the float level, the float moves to a vertical position, the influence of the float magnetic field is removed from the reed switch, and the normally open reed switch contacts open. When the fluid level in the washer reservoir falls below the level of the pivoting float, the float moves to a horizontal position, the influence of the float magnetic field is applied to the reed switch, and the contacts of the normally open reed switch close.
The washer fluid level switch is connected to the vehicle electrical system through a dedicated take out and connector of the headlamp and dash wire harness. The switch is connected in series between ground and the washer fluid switch sense input to the ElectroMechanical Instrument Cluster (EMIC). The switch receives a path to ground at all times through another take out of the headlamp and dash wire harness with a single eyelet terminal connector that is secured under a ground screw near the front of the left front fender inner shield in the engine compartment. When the switch closes, the EMIC senses the ground on the washer fluid switch sense circuit. The EMIC is programmed to respond to this input by illuminating the washer fluid indicator and by sounding an audible chime tone warning.
The washer fluid level switch input to the EMIC can be diagnosed using conventional diagnostic tools and methods. (Refer to INSTRUMENT CLUSTER/WASHER FLUID INDICATOR - DIAGNOSIS AND TESTING).
Fig.18 Washer Pump/Install:
WASHER PUMP/MOTOR
The washer pump/motor unit is located on the outboard side of the washer reservoir on the outboard side of the right front frame rail behind the right front wheel house splash shield. A small permanently lubricated and sealed reversible electric motor is coupled to the rotor-type washer pump. The use of an integral shuttle valve allows the washer pump/ motor unit to provide washer fluid to either the front or the rear washer systems, depending upon the direction of the motor/pump impeller rotation. A seal flange with a barbed inlet nipple on the pump housing passes through a rubber grommet seal installed in a dedicated mounting hole of the washer reservoir. When the pump is installed in the reservoir the front barbed outlet nipple on the pump shuttle valve housing connects the unit to the front washer hose and the rear barbed outlet nipple connects the unit to the rear washer hose. The letters "F" and "R" molded into the shuttle valve housing adjacent to each nipple provide further clarification of the nipple assignments.
The washer pump/motor unit is retained on the reservoir by the interference fit between the barbed pump inlet nipple and the grommet seal, which is a light press fit. The top of the washer pump is also secured to the washer reservoir by the use of a snap post on the motor and a snap post receptacle molded into the reservoir that allows for mounting of the washer pump without the use of fasteners. An integral connector receptacle on the top of the motor housing connects the unit to the vehicle electrical system through a dedicated take out and connector of the headlamp and dash wire harness. The washer pump/motor unit cannot be repaired. If faulty or damaged, the entire washer pump/motor unit must be replaced.
The washer pump/motor unit features a reversible electric motor. The direction of the motor is controlled by hard wired outputs from the momentary front and rear washer switch circuitry contained within the right (wiper) control stalk of the multi- function switch. When battery current and ground are applied to the two pump motor terminals, the motor rotates in one direction. When the polarity of these connections is reversed, the motor rotates in the opposite direction. When the pump motor is energized, the rotor-type pump pressurizes the washer fluid and forces it through one of the two pump outlet nipples, and into the front or rear washer plumbing.
Fig.19 Washer Pump Fluid Flow:
Washer fluid is gravity-fed from the washer reservoir to the inlet port of the washer pump housing. An integral shuttle valve is located in a housing on the outlet port side of the pump housing. This shuttle valve controls which washer system plumbing receives the washer fluid being pressurized by the pump. When the pump impeller rotates in the counterclockwise direction (viewed from the bottom), pressurized washer fluid is pushed out the front washer system port and biases the shuttle valve to the left, sealing off the rear washer system outlet nipple. When the pump impeller rotates in the clockwise direction (viewed from the bottom), pressurized washer fluid is pushed out the rear washer system port and biases the shuttle valve to the right, sealing off the front washer system outlet nipple.
The washer pump/motor unit can be diagnosed using conventional diagnostic tools and methods.
Fig.22 Washer Reservoir:
WASHER RESERVOIR
A single washer fluid reservoir is used for both the front and rear washer systems. The molded plastic washer fluid reservoir is mounted on the outboard side of the right front frame rail in front of the right front wheel, where it is concealed by the right front wheel house splash shield. The only visible component of the washer reservoir is the filler neck and cap unit, which extends through a hole in the right front wheel house extension panel into the engine compartment. A bright yellow plastic filler cap with an integral bail strap and filler neck mounting bracket is labeled with an International Control and Display Symbol icon for "Windshield Washer" and the text "Washer Fluid Only" molded into it. The cap snaps over the open end of the filler neck.
There is a dedicated hole on the outboard side of the reservoir provided for the mounting of the washer pump/motor unit, and another dedicated hole on the rear of the reservoir for the washer fluid level switch. A snap post receptacle molded into the reservoir allows for mounting of the washer pump without the use of fasteners. The reservoir also features integral hose routing troughs on its outboard side and integral routing clips along its top. The washer reservoir is secured to the outboard side of the right front frame rail by two screws and an integral molded tab that engages in a slot in the right front frame rail. Another screw secures the reservoir filler neck to the upper radiator crossmember in the front of the engine compartment. The right front fender wheel house splash shield must be removed to access the washer reservoir for service.
The washer fluid reservoir provides a secure, on-vehicle storage location for a large reserve of washer fluid for operation of the front and rear washer systems. The washer reservoir filler neck provides a clearly marked and readily accessible point from which to add washer fluid to the reservoir. The washer/pump motor unit is located in a sump area near the front of the reservoir to be certain that washer fluid will be available to the pump as the fluid level in the reservoir becomes depleted. The washer pump/motor unit is mounted in the lowest position in the sump. The washer fluid level switch is mounted just above the sump area of the reservoir so that there will be adequate warning to the vehicle operator that the washer fluid level is low, before the washer system will no longer operate.
Fig.25 ISO Micro Relay:
WIPER HIGH/LOW RELAY
The wiper high/low relay is located in the Power Distribution Center (PDC) in the engine compartment near the battery. The wiper high/low relay is a conventional International Standards Organization (ISO) micro relay. Relays conforming to the ISO specifications have common physical dimensions, current capacities, terminal patterns, and terminal functions. The relay is contained within a small, rectangular, molded plastic housing and is connected to all of the required inputs and outputs by five integral male spade-type terminals that extend from the bottom of the relay base.
The wiper high/low relay cannot be adjusted or repaired and, if faulty or damaged, the unit must be replaced.
The wiper high/low relay is an electromechanical switch that uses a low current input from the Body Control Module (BCM) to control a high current output to the front wiper motor. The movable common feed contact point is held against the fixed normally closed contact point by spring pressure. When the relay coil is energized, an electromagnetic field is produced by the coil windings. This electromagnetic field draws the movable relay contact point away from the fixed normally closed contact point, and holds it against the fixed normally open contact point. When the relay coil is de-energized, spring pressure returns the movable contact point back against the fixed normally closed contact point. A resistor is connected in parallel with the relay coil in the relay, and helps to dissipate voltage spikes and electromagnetic interference that can be generated as the electromagnetic field of the relay coil collapses.
The wiper high/low relay terminals are connected to the vehicle electrical system through a connector receptacle in the Power Distribution Center (PDC). The inputs and outputs of the wiper high/low relay include:
- Common Feed Terminal - The common feed terminal (30) is connected to the output of the wiper ON/OFF relay at all times through the wiper ON/OFF relay output circuit.
- Coil Ground Terminal - The coil ground terminal (85) is connected to a control output of the Body Control Module (BCM) through a front wiper high/ low relay control circuit. The BCM controls front wiper motor operation by controlling a ground path through this circuit.
- Coil Battery Terminal - The coil battery terminal (86) receives battery current at all times from a circuit breaker in the Junction Block (JB) through a fused ignition switch output (RUN/ACC) circuit.
- Normally Open Terminal - The normally open terminal (87) is connected to the high speed brush of the front wiper motor through a front wiper high/low relay high speed output circuit, and is connected to the high speed brush whenever the relay is energized.
- Normally Closed Terminal - The normally closed terminal (87A) is connected to the low speed brush of the front wiper motor through a front wiper high/low relay low speed output circuit, and is connected to the low speed brush whenever the relay is de-energized.
The wiper high/low relay can be diagnosed using conventional diagnostic tools and methods.
Fig.28 ISO Micro Relay:
WIPER ON/OFF RELAY
The wiper ON/OFF relay is located in the Power Distribution Center (PDC) in the engine compartment near the battery. The wiper ON/OFF relay is a conventional International Standards Organization (ISO) micro relay. Relays conforming to the ISO specifications have common physical dimensions, current capacities, terminal patterns, and terminal functions. The relay is contained within a small, rectangular, molded plastic housing and is connected to all of the required inputs and outputs by five integral male spade-type terminals that extend from the bottom of the relay base.
The wiper ON/OFF relay cannot be adjusted or repaired and, if faulty or damaged, the unit must be replaced.
The wiper ON/OFF relay is an electromechanical switch that uses a low current input from the Body Control Module (BCM) to control a high current out-put to the front wiper motor. The movable common feed contact point is held against the fixed normally closed contact point by spring pressure. When the relay coil is energized, an electromagnetic field is produced by the coil windings. This electromagnetic field draws the movable relay contact point away from the fixed normally closed contact point, and holds it against the fixed normally open contact point. When the relay coil is de-energized, spring pressure returns the movable contact point back against the fixed normally closed contact point. A resistor is connected in parallel with the relay coil in the relay, and helps to dissipate voltage spikes and electromagnetic interference that can be generated as the electromagnetic field of the relay coil collapses.
The wiper ON/OFF relay terminals are connected to the vehicle electrical system through a connector receptacle in the Power Distribution Center (PDC).
The inputs and outputs of the wiper ON/OFF relay include:
- Common Feed Terminal - The common feed terminal (30) is connected to the common feed terminal of the wiper high/low relay at all times through the wiper ON/OFF relay output circuit.
- Coil Ground Terminal - The coil ground terminal (85) is connected to a control output of the Body Control Module (BCM) through a front wiper ON/OFF relay control circuit. The BCM controls front wiper motor operation by controlling a ground path through this circuit.
- Coil Battery Terminal - The coil battery terminal (86) receives battery current at all times from a circuit breaker in the Junction Block (JB) through a fused ignition switch output (RUN/ACC) circuit.
- Normally Open Terminal - The normally open terminal (87) receives battery current at all times from a circuit breaker in the Junction Block (JB) through a fused ignition switch output (RUN/ACC) circuit, and provides battery current to the front wiper ON/OFF relay output circuit whenever the relay is energized.
- Normally Closed Terminal - The normally closed terminal (87A) is connected to the wiper park switch in the front wiper motor through the front wiper park switch sense circuit, and is connected to the wiper park switch whenever the relay is de-energized.
The wiper ON/OFF relay can be diagnosed using conventional diagnostic tools and methods.