Lamp Strategy

The following strategy for the FCM controlled transfer case system uses the instrument cluster VF display's 4LOCK, 4LO, Service 4WD, and Mode Switch Transfer Case Neutral LED. Flashing any of the lamps or LED is accomplished at a 2Hz rate. 

• 2WD or AWD to 4LO - Successful shifts will flash 4LO during a shift, then after the 4LO position has been met, display the 4LO lamp solid. In the blocked condition, flash the 4LO lamp during the 5 Phase 1 shift attempts. After 5 unsuccessful attempts, the transfer case remains in 2WD or AWD and no lamps are illuminated. When shift conditions are not met, no shift attempts are made and the 4LO lamp is flashing. 
• 2WD or AWD to 4LOCK - Successful shifts will flash 4LOCK during a shift, then after the 4LOCK position has been met, display the 4LOCK lamp solid. In the blocked condition, flash the 4LOCK lamp during the 5 Phase 1 shift attempts. After 5 unsuccessful attempts, the transfer case remains in 2WD or AWD and no lamps are illuminated. When shift conditions are not met, no shift attempts are made and the 4LOCK lamp is flashing. 
• 4LOCK to 4LO - Successful shifts will turn off the 4LOCK lamp and flash 4LO during a shift, then after the 4LO position has been met, display the 4LO lamp solid. In the blocked condition, turn off 4LOCK and flash the 4LO lamp during the 5 Phase 1 shift attempts. After 5 unsuccessful attempts, the transfer case remains in 4LOCK and the 4LOCK lamp turns on solid. When shift conditions are not met, the 4LOCK lamp remains illuminated solid and the 4LO lamp is flashing. 
• 4LOCK to 2WD or AWD - Successful shifts will flash the 4LOCK lamp during a shift, then after the 2WD or AWD position has been met, turn off the 4LOCK lamp. In the blocked condition, flash the 4LOCK lamp during the 5 Phase 1 shift attempts. After 5 unsuccessful attempts, the transfer case remains in 4LOCK and the 4LOCK lamp turns on solid. When shift conditions are not met, no shift attempts are made and the 4LOCK lamp is flashing. 
• 4LO to 2WD or AWD - Successful shifts will flash the 4LO lamp during a shift, then after the 2WD or AWD position has been met, turn off the 4LO lamp. In the blocked condition, flash the 4LO lamp during the 5 Phase 1 shift attempts. After 5 unsuccessful attempts, the transfer case remains in 4LO and the 4LO lamp turns on solid. When shift conditions are not met, no shift attempts are made and the 4LO lamp is flashing. 
• 4LO to 4LOCK - Successful shifts will turn off the 4LO lamp and flash 4LOCK during a shift, then after the 4LOCK position has been met, display the 4LOCK lamp solid. In the blocked condition, turn off 4LO and flash the 4LOCK lamp during the 5 Phase 1 shift attempts. After 5 unsuccessful attempts, the transfer case remains in 4LO and the 4LO lamp turns on solid. When shift conditions are not met, the 4LO lamp remains illuminated solid and 4LOCK is flashing. 
• 2WD or AWD to NEUTRAL - Successful shifts have no lamps illuminated, then after the NEUTRAL position has been met, display the NEUTRAL LED solid. In the blocked condition, no lamps are illuminated during the 5 Phase 1 attempts. After 5 unsuccessful attempts, the transfer case remains in 2WD or AWD and no lamps are illuminated. When shift conditions are not met, flash the NEUTRAL lamp while the push button is depressed. 
• 4LOCK to NEUTRAL - Successful shifts have no lamps illuminated, then after the NEUTRAL position has been met, display the NEUTRAL LED solid. In the blocked condition, no lamps are illuminated during the 5 Phase 1 attempts. After 5 unsuccessful attempts, the transfer case remains in 4LOCK and the 4LOCK lamp is illuminated. When shift conditions are not met, flash the NEUTRAL lamp while the push button is depressed. 
• 4LO to NEUTRAL - Successful shifts have no lamps illuminated, then after the NEUTRAL position has been met, display the NEUTRAL LED solid. In the blocked condition, no lamps are illuminated during the 5 Phase 1 attempts. After 5 unsuccessful attempts, the transfer case remains in 4LO and the 4LO lamp is illuminated. When shift conditions are not met, flash the NEUTRAL lamp while the push button is depressed. 
• NEUTRAL to 2WD or AWD - Successful shifts have no lamps illuminated, then after the 2WD or AWD position has been met, no lamps are illuminated. In the blocked condition, no lamps are illuminated during the 5 Phase 1 attempts. After 5 unsuccessful attempts, Phase 2 shifting will continue until the transfer case is in the 2WD or AWD or 4LO position. If the final position is 2WD or AWD, no lamp is illuminated, if the final position is 4LO, illuminate the 4LO lamp. When shift conditions are not met, flash the 4LOCK and 4LO lamps and the NEUTRAL LED remains solid while the push button is depressed, 
• Neutral to 4LOCK - Successful shifts will flash the 4LOCK lamp during a shift, then after the 4LOCK position has been met, display the 4LOCK lamp solid. In a blocked condition, the 4LOCK lamp will flash during the 5 Phase 1 attempts. After 5 unsuccessful attempts, continue to flash the 4LOCK, Phase 2 shifting will continue until the transfer case is in the 2WD or AWD or 4LO position. If the final position is 2WD or AWD, turn off the 4LOCK lamp, if the final position is 4LO, illuminate the 4LO lamp. When shift conditions are not met, flash the 4LOCK and 4LO lamps and the NEUTRAL LED remains solid while the push button is depressed. 
• NEUTRAL to 4LO - Successful shifts will flash the 4LO lamp during a shift, then after the 4LOCK position has been met, display the 4LO lamp solid. In a blocked condition, the 4LO lamp will flash during the 5 Phase 1 attempts. After 5 unsuccessful attempts, continue to flash 4LO, Phase 2 shifting will continue until transfer case is in the 2WD or AWD or 4LO position. If the final position is 2WD or AWD, turn off the 4LO lamp, if the final position is 4LO, illuminate the 4LO lamp solid. When shift conditions are not met, flash the 4LOCK and 4LO lamps and the NEUTRAL LED remains solid while push the button is depressed.