Principles of Operation (How Does It Work?)
PRINCIPLES OF OPERATIONNAVIGATOR - ONE TOUCH UP/DOWN
NOTE: The LF window motor is not on the multiplex link.
The LF window motor is an eight-pin motor with integral electronics. The front window control switch sends three separate signals to the LF window motor: up, down and AUTO. The front window control switch provides a 12-volt signal to the motor to request an up or down operation. When AUTO up or AUTO down are requested, the front 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 and down contacts are tied to ground and the AUTO contact is floating within the front window control switch when the switch is in the neutral position. The up, down and AUTO feeds to the motor are all low current.
The LF 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 three 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 LF window motor operates with the ignition switch in the RUN/ACC positions only (and delayed accessory) and is sensed via the delayed accessory and logic ground inputs. 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 either logic or motor ground will cause this system to become inoperative. For correct functionality, both power feeds and both ground feeds 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 between 4 and 200 mm (0.15-7.9 inch) of window opening, the bounce-back position will be 250 mm (9.8 inch) of window opening. If an obstruction occurs at a position greater than 200 mm (7.9 inch) of window opening, the bounce-back position will be 50 mm (2 inch) below where the obstruction occurred.
The LF 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 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 up (and down) movement of the window until the LF window motor stalls the window glass into the upper header seat. If no internal or external faults are present, the motor will automatically resume normal (full) operation.
The front window control switch is supplied with illumination 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 window. The front window control switch uses the delayed accessory power input which is transferred to the up or down outputs via closing of a switch contact. The front window control switch uses the main switch ground input which is transferred to the AUTO output via closing of a switch contact. If the delayed accessory feed to the front window control switch is missing, none of the windows will function. If the main ground signal is missing, the LF AUTO functions will be inoperative and the remaining three windows will also be inoperative.
If the front 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 LF window will only move down or one touch down. If the down contact or associated wiring develops an open circuit, the LF window will only move up or one touch up. If the auto contact or associated wiring develops an open circuit, the LF window will only move proportionally up or down.
The LF 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 LF window will appear to be inoperative if a switch error is present.
A new LF 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 front window control switch is released. If the LF window motor is removed from the window regulator drum housing, or if a new LF window motor is installed, the LF window motor must be initialized. Refer to Door Window Motor Initialization in the General Procedures.
The LF window motor will automatically adjust to system changes throughout its life: changes in seat drag and slight changes in the fully open position will occur and are automatically compensated for. Once initialized, for the most part, the LF window motor will soft stall into the upper and lower positions contributing to extended durability of the system. If the LF window does not seal completely in the full up position (very small gaps/non bounce-back events only), the LF window switch can be actuated to the proportional up position and the window will be energized long enough to fully seal (for a small fraction of a second) and this new position will be learned.
Expedition - One Touch Down
The one touch down feature for the Expedition is controlled by the driver window control switch.
Rear Window Defrost
The instrument cluster module (ICM) receives a signal from the rear window defrost switch. The ICM then grounds the rear window defrost relay to turn ON and time the rear window defrost grid.