Principles of Operation
PRINCIPLES OF OPERATIONNavigator - One-Touch Up/Down, Front Windows
NOTE: The LF and RF window motors are not on the multiplex link.
The LF and RF window motors have 8 pins and contain integral electronics. The master window control switch sends 3 separate signals to the LF or RF window motor (the passenger window control switch sends 3 separate signals to the RF window motor only): UP, DOWN and AUTO. The master window control switch or passenger window control switch provide a 12-volt signal to the motor to request an up or down operation. When AUTO up or AUTO down are requested, the window control switch provides a 12-volt signal on the UP or DOWN line and a ground signal on the AUTO line simultaneously. The UP, DOWN and AUTO contacts are floating within the front control switches (LF, RF) when the switches are in the NEUTRAL position. The LF and RF window motors pull the UP and DOWN inputs to ground and the AUTO input to 12 volts when the wire harness is connected to the motor and signals are not being provided by the window switches. The up, down and auto feeds to the motor are all low current.
The window motor plastic pinion gear is mated to the drum housing of a dual rail drum and cable window regulator. The motor is attached to the drum housing (plastic) by 3 screws. The motor uses internal Hall-effect sensor feedback coupled to the microprocessor to determine window position and operate the window. If the Hall-effect pulses are not being received by the microprocessor, the motor will run for approximately 1/10 second each switch press. The motor contains a thermal breaker to protect the motor windings from overcurrent/overtemperature operation. Continued successive operation of the motor will cause the thermal breaker to open, causing a loss of function until the motor cools.
The window motor operates with the ignition switch in the RUN/ACC positions only (and delayed accessory) and is sensed via the delayed accessory input. The motor is supplied with B+ power and draws a key-off load of approximately 3/4 mA. All of the high current required to move the window is supplied through the B+ and motor ground inputs. The loss of motor ground will cause this system to become inoperative. For correct functionality, both power feeds and the ground feed must be intact at the motor.
During an auto up or auto down function, movement of the window can be stopped by actuating the switch to any position (UP, DOWN, AUTO up, AUTO down). The switch must then be released before the window will perform the next commanded movement.
When an obstacle has been detected in the window opening as the window is moving upward, the window will automatically reverse direction and move toward the fully open position (in both proportional up and one-touch up modes). This is known as "bounce-back". Once the window stops at its bounce-back position, and within 2 seconds the switch is released, then held in the AUTO UP position, the window will travel up with no bounce-back protection (security override). If the switch is released before the window reaches fully closed, the window will stop with bounce-back automatically re-enabled for the next window up movement. If the ignition switch is turned to OFF or START (without delayed accessory), the window will stop. The only exception is when an obstacle is detected while delayed accessory is lost. In this case the window will bounce back, then stop. Ice, contaminant buildup and environmentally induced tight spots in the window seals are all possible uses for the security override feature.
If an obstruction occurs while the window is moving up, the window will bounce back 125 mm (4.9 in) from where the obstruction occurs. If an obstruction occurs when the window is 125 mm (4.9 in) or less from the DOWN position, the bounce back position will be the full DOWN position.
The LF and RF window motor will retain its initialization (memory) if power (B+) is removed while the window is not in motion. If power (B+) is disconnected from the LF or RF window motor while the window is in motion, the motor will enter position recovery mode when power is restored (AUTO up and AUTO down functions are disabled). Position recovery mode allows proportional down (and up) movement of the window until the window motor stalls the window glass in the full DOWN position. If no internal or external faults are present, the motor will automatically resume normal (full) operation.
The master window control switch and passenger window control switch are supplied with illumination power and illumination ground inputs used to illuminate the switch when the headlamp switch is turned to the PARK or ON position (the AUTOLAMP position may also energize this input). These switch inputs do not directly affect operation of the LF or RF window. The master window control switch and passenger window control switch use the delayed accessory power input which is transferred to the UP or DOWN outputs via closing of a switch contact. The master window control switch and passenger window control switch each have separate ground switch inputs which are transferred to the auto output via closing of a switch contact. If the delayed accessory feed to the window control switch is missing, none of the windows will function. If the master window control switch ground signal is missing, the auto functions will be inoperative and the LR and RR windows will also be inoperative. The RF window auto functions will still operate correctly from the passenger window control switch as long as the ground feed to that switch is present.
If the window control switch, or its associated wiring, develops an open circuit, that function will become inoperative. If the UP contact or associated wiring develops an open circuit, the window will only move down or one-touch down. If the DOWN contact or associated wiring develops an open circuit, the window will only move up or one-touch up. If the auto contact or associated wiring develops an open circuit, the window will only move proportionally up or down.
The window motor will suspend window operation if a switch error exists. A switch error is defined as UP and DOWN, AUTO without UP or DOWN, or UP and DOWN and AUTO energized at the same time. The window will appear to be inoperative if a switch error is present.
A new LF or RF window motor will be in proportional up/down mode prior to initialization. The motor will respond to a proportional UP or DOWN switch actuation only and bounce back is disabled. If the switch is actuated to the AUTO up or AUTO down position and released, window movement will stop when the UP or DOWN contact in the master window control switch or passenger window control switch is released. If the window motor is removed from the window regulator drum housing, or if a new window motor is installed, the window motor must be initialized. Refer to Window Motor Initialization in the General Procedures portion of this section.
The window motor will automatically adjust to system changes throughout its life: changes in seal drag and slight changes in the fully open position will occur and are automatically compensated for. Once initialized, for the most part, the window motor will soft stall into the lower position contributing to extended durability of the system. If the window does not seal completely in the full up position, the window switch can be actuated to the proportional up position and the window will be energized long enough to fully seal. If the window does not travel fully down, the window switch can be activated to the proportional DOWN position and the window will be energized long enough to travel to the full DOWN position. In both cases, the new positions will be learned.
Expedition - One-Touch Down
The one-touch down feature for the Expedition is controlled by the master window control switch.
Rear Window Defrost
When the rear window defrost switch is pressed, the electronic automatic climate control (EATC) or electronic manual temperature control (EMTC) will activate the heated backlight relay located in the battery junction box (BJB). When the heated backlight relay is active, the heated backlight will be energized.