WHICH RELAY WIRE IS THE ONE FOR THE 4X4 ON THE TRANSFER CASE? WHICH COLOR IS THE CONNECTOR?

Have you checked the fuse or loose wiring? Tighten the ground wire firmly.

Manual shift or Four-Wheel Drive Systems - Electronic Shift I'm assuming you have electronic shift because you refer to relay clicking behind the instrument panel . Principles of Operation Transfer Case - Electronic Shift
The four-wheel drive, electronic shift-on-the-fly feature electrically shifts the vehicle transfer case between 2WD, 4X4 HIGH, and 4X4 LOW. The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. The operator is informed which mode the system is in by two instrument cluster indicators, one for 4X4 HIGH which is 4X4, and one for 4X4 LOW which is LOW RANGE (in 4X4 LOW both the lamps are on). Shifts into 4X4 HIGH can be made at any speed. When shifting into 4X4 HIGH with the vehicle stationary, tooth blockage may occur, preventing shift completion. When the vehicle is driven above 8 km/h (5mph) the shift will complete. When shifting in or out of 4X4 LOW, the generic electronic module (GEM) requires that the vehicle speed be less than 5 km/h (3 mph), the brake pedal be applied, and the transmission in NEUTRAL (automatic transmission) or the clutch pedal be depressed (manual transmission). (The digital transmission range [TR] sensor informs the GEM when the automatic transmission is in the NEUTRAL range position.)
The gearmotor encoder assembly is mounted externally on the transfer case. It drives a rotary cam which moves the mode fork and the range fork within the transfer case between the 4X4 HIGH, 4X4 LOW, and 2WD range positions.
The GEM uses two relays to control the gearmotor encoder assembly shift between 4X4 HIGH, 4X4 LOW, and 2WD modes. The GEM controls the pulse vacuum hublock (PVH) solenoid which supplies engagement and disengagement vacuum to control the hublocks.
The GEM accomplishes shifts by interpreting inputs from:

• mode select switch (MSS)
• vehicle speed signal (transmitted from the ABS system)
• gearmotor encoder plate position
• brake pedal switch
• digital transmission range (TR) sensor (automatic transmission)
• clutch pedal position (CPP) switch (manual transmission)
• ignition switch

Based on these inputs, the GEM controls the shifts into 2WD, 4X4 HIGH, or 4X4 LOW with the following outputs:

• low to high relay (clockwise)
• high to low relay (counterclockwise)
• pulse vacuum hublock (PVH) solenoid
• gearmotor encoder assembly

The electronic shift-on-the-fly (ESOF) system has a feature which allows the driver to override the vacuum operated hublocks. When the front hublocks are manually turned to the LOCK position, the hublocks are locked at all times, overriding the vacuum operated system. If the front hublocks are manually turned to the AUTO position, the hublocks can only be locked by turning the MSS to 4X4 HIGH or 4X4 LOW position.
Do you know what DTC'S - diagnostic trouble code's are ?
GEM Diagnostic Trouble Code (DTC) Index
GEM Diagnostic Trouble Code (DTC) Index DTC Description Source Action C1728 Transfer Case Unable to Transition Between 2H and 4H GEM CARRY OUT the electronic shift function test. REFER to Function Test - Electronic Shift in this section. C1729 Transfer Case Unable to Transition Between 4H and 4L GEM CARRY OUT the electronic shift function test. REFER to Function Test - Electronic Shift in this section. P0500 Vehicle Speed Sensor (VSS) Malfunction GEM GO to Pinpoint Test F . P1804 Transmission 4-Wheel Drive High Indicator Circuit Failure GEM GO to Pinpoint Test H . P1808 Transmission 4-Wheel Drive Low Indicator Circuit Failure GEM GO to Pinpoint Test I . P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure GEM GO to Pinpoint Test E . P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground GEM GO to Pinpoint Test E . P1819 Transmission Park/Neutral Position Switch Short Circuit to Ground GEM GO to Pinpoint Test F . P1820 Transmission Transfer Case Clockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test E . P1822 Transmission Transfer Case Clockwise Shift Relay Coil Short to Battery GEM GO to Pinpoint Test E . P1828 Transfer Case Counterclockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test E . P1830 Transmission Transfer Case Counterclockwise Shift Relay Coil Short Circuit to Battery GEM GO to Pinpoint Test E . P1832 Transmission Transfer Case Differential Lockup Solenoid Circuit Failure GEM GO to Pinpoint Test G . P1834 Transmission Transfer Case Differential Lockup Solenoid Short Circuit to Battery GEM GO to Pinpoint Test G . P1865 Transmission Transfer Case Contact Plate Power Short to Ground GEM GO to Pinpoint Test E . P1866 Transmission Transfer Case System Concern - Servicing Required GEM CARRY OUT the electronic shift function test. REFER to Function Test - Electronic Shift in this section. P1867 Transmission Transfer Case Contact Plate General Circuit Failure GEM GO to Pinpoint Test E . P1876 Transmission Transfer Case 2-Wheel Drive Solenoid Circuit Failure GEM GO to Pinpoint Test G . P1877 Transmission Transfer Case 2-Wheel Drive Solenoid Circuit Short to Battery GEM GO to Pinpoint Test G .
Your best bet , take it to a qualified repair shop .

it needs a new 4x4 module it is located behind the glove box. but it needs to beprogrammed at the dealer . sorry

Hi, it sounds like your front diff engages but your transfer case is not. raise one of your front tires off the ground and see if it will lock up when you go to 4hi. If it does then the problem is your encoder motor that hangs down under your transfer case.

If you have an electric shift transfer case, (little knob to change to 4x4), then the motor may have gone out. There are several fuses and relays associated with the 4x4. Check all of the fuses, replace any that are burnt out. You can not check relays, so you will have to replace them. If this does not solve the problem, then the problem could be in the 4x4 mini-computer, or the motor could be burnt out, or the transfer case could be locked up. On most ford transfer cases you can take off the bolts that hold on the electric shifter motor, and manually turn the knob that changes from 2x4-4x4. If that know will not turn with the vehicle in neutral, the transfer case may be locked up. If it is not the transfer case, look into finding a new motor for the transfer case.

Electronic Shift On the Fly (ESOF) Operation
The ESOF system is an electronic shift 4x4 system that allows the operator to choose between two different 4x4 modes as well as 2-wheel drive. The operator can switch between 2WD and 4WD HIGH mode at speed. To engage or disengage LOW Range, the vehicle speed must be less than 5 kph, the brake depressed, and the transmission must be in NEUTRAL.

The transfer case is equipped with an electromagnetic clutch which is located inside the case. This clutch is used to spin up the front drive-line when shifting from 2WD to 4x4 High mode at speed. When the control switch on the instrument panel is turned, the generic electronic module (GEM) recognizes that a shift has been requested and activates the electromagnetic clutch and the relays which power the transfer case shift motor. When the shift motor reaches the desired position as determined by the contact plate position inputs to the GEM, power to the shift relays and motors will be removed. When the transfer case front and rear output shafts are synchronized, the spring loaded lockup collar mechanically engages the main-shaft hub to the drive sprocket. Finally, the front axle collar is engaged and the electromagnetic clutch is deactivated.

Shift Between 2WD and 4x4 HIGH:
Shifts between 2WD and 4x4 HIGH can be made at speed. Listed below are the inputs and outputs needed by the GEM to execute a change between any of these modes.

Feature Inputs:
*4WD Mode Switch (Various resistances).
*Contact Plate Position Inputs A, B, C, D (grounded when closed, open circuit when open).

Feature Outputs:
*4x4 Shift Motor Relay Outputs
*Transfer Case Clutch Relay (grounded when relay is on, open circuit when relay is off).
*4x2/4x4 Vacuum Solenoid (grounded when activated, open circuit when deactivated).
*Cluster Indicators (ground when activated, open circuit when deactivated).

Shifting Into/Out of 4WD LOW:
When shifting into or out of 4WD LOW, the GEM requires that the vehicle speed be less than 5 kph, the brake is applied, and the transmission is in NEUTRAL.

Feature Inputs:
*4WD Mode Switch (Various resistances).
*Contact Plate Position Inputs A, B, C, D (grounded when closed, open circuit when open).
*VSS Sensor (Sinusoid Signal: 0.7V-20V, 2.2 Hz/mph).
Brake Input (battery voltage when brake is depress, open circuit when not activated).
*Transmission Range Sensor (grounded when transmission is in NEUTRAL, open circuit otherwise).
8Start/Clutch Depressed Input

Feature Outputs:
*4x4 Shift Motor Relay Outputs
*4x2/4x4 Vacuum Solenoid (grounded when activated, open circuit when deactivated).
*Cluster Indicators (grounded when activated, open circuit when deactivated).

4WD Mode Switch
A rotary switch allows the vehicle operator to choose between 2WD, 4WD HIGH, and 4WD LOW modes of 4x4 operation.

GEM Module
The Generic Electronic Module (GEM) controls the operation of the 4x4 system

Vehicle Speed Sensor
The vehicle speed sensor (VSS), mounted in the rear of the transfer case, informs the GEM of the vehicle speed.

Transfer Case Shift Motor Sense Plates

The shift motor sense plate, an integral part of the electric shift motor, informs the GEM to the positions of the transfer case

Transmission Range Sensor
Located on the left side of the transmission, this sensor informs the GEM when the transmission is in the NEUTRAL position.

Electric Shift Motor
The electric shift motor, mounted externally at the rear of the transfer case, drives a rotary cam which moves the mode fork and range fork within the transfer case to select between the 2WD, 4WD HIGH, and 4WD LOW positions.

4x4/4x2 Vacuum Solenoids
These two solenoids are attached to the upper RH side of the engine compartment dash, and alternately route vacuum to the vacuum motor which engages/disengages the center axle disconnect collar in the front axle assembly.

4x4 Shift Motor Relay
A module containing two relays which under the control of the GEM, shift the transfer case shift motor between the 2WD, 4WD HIGH, and 4WD LOW modes.

Transfer Case Clutch Relay
An electromechanical relay is used to activate the transfer case clutch within the transfer case.

Good luck and hope this helps,but start with the simple and check the fuses and wire harness. Both white/light blue stripe wires should have 12V in run. The GEM will ground the left side (closest to engine) solenoid to disengage the front axle. It will ground the the right side solenoid (closest to fender) to engage the front axle. If the GEM doesn't see Neutral it will not let the truck come out of 4Lo. If the GEM had water leaking on it it may well be the root of the problem. The shift motor only has power when the GEM sends it a signal to move the shift lever. Once the shift is completed the motor shuts off. There are 2 wires that control the shift motor. A yellow and an orange. The GEM alternates between 12v and Ground to these wires to control which way the motor turns. The GEM uses the transfer case shift relay module to control the power to the motor. There are contact plates inside the shift motor assembly that indicate the position that the shift lever is in. This is what the GEM used to know what the T-case is doing. Any one of these components can fail.

Check the fuse to the 4x4, if the fuse is good then check the 4x4 electric motor actuator on the transfer case. You should hear it work from 2wd, 4hi to 4low and back to 2wd with the push of the switch. if you don't hear it working then check the wire harness at the actuator motor, look for any damages like corrosion or cracked wire connector clips. If the 4x4 actuator is working on the transfer case, then the front hub 4x4 actuator may have gone bad and that's located on the front differential. It's common for the clip there to corrode and break and is an easy fix with a new collar pin, at worst it's the diaphragm on the vacuum actuator that is located under the battery tray. There is a vacuum switch on the top of the transfer case, driver side but when that fails, your front hub stay's locked in the on position. Good luck and keep me posted and hope it's a simple fuse that has gone bad. You can pick up all these parts at Auto Zone or Parts Source and they will have the step by step instructions for you to get the job done with common tools.

Check BJB ( aka Battery Junction Box, Engine Compartment fuse panel ) Fuse #17. This is the power to the Transfer Case shift relay, which powers the Shift motor in the Transfer case and power to the magnetic clutch coil ( via the transfer case relay ).

The other fuse to check is the CJB ( aka Central Junction Box, cab fuse panel ) Fuse #23.

If both fuses check good, time to check for power on the connector for the shift relay and the shift motor. The power from BJB Fuse # 17 is the Dark Green w/ Light Green stripe ( this is hot at all times ).
The old school test is to lightly hit the back of the transfer case, to see if the shift motor is hung up.
Here are the diagrams, so you can see what I am talking about.

Do you need the engine harness, dash harness.? where is your problem?

2-Speed Torque-On-Demand (TOD) Operation
The automatic 4-wheel drive (A4WD) system is a 2-speed torque-on-demand (TOD) operation that utilizes the following components:

• Transfer case
• 4-wheel drive (4WD) control module (integral to the powertrain control module [PCM])
• Mode select switch (MSS)
• Gearmotor encoder assembly (part of the transfer case shift motor)
• Transfer case shift motor
• Shift motor sense plate (part of the gearmotor encoder assembly)

Principles of Operation
Transfer Case Shift Motor The externally mounted transfer case shift motor, located at the rear of the transfer case, turns the shift cam assembly. As the shift cam assembly turns, it positions the reduction shift fork for desired transfer case operation. An integral position sensor in the shift motor provides shift motor position information to the 4WD control module.
Mode Select Switch (MSS) The push button MSS, mounted on the instrument panel, allows the operator to select the 4x4 Auto, 4x4 High, and 4x4 Low transfer case operating modes. The indicator light, on the instrument cluster push button, will illuminate only when the 4x4 Low position is engaged.
Visual Inspection Chart Mechanical Electrical

• Axle shafts and CV joints
• Driveshaft and universal joints
• Fluid leaks
• Matching tire sizes
• Transfer case shift motor

• Battery junction box (BJB) fuses:
  • 8 (30A)
  • 17 (5A)
  • 18 (20A)
• Central junction box (CJB) fuses:
  • 12 (5A)
  • 24 (15A)
• 4x4 module (PCM)
• Wiring harness
• Gearmotor encoder contact plate
• Connector(s)
• Circuitry
• Mode indication switch (MSS)

1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

1. If the concern is not visually evident, connect the diagnostic tool to the data link connector and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
   • check that the program card is correctly installed.
   • check the connections to the vehicle.
   • check the ignition switch position.

1. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.

1. Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
   • CAN circuit fault; all electronic control units no response/not equipped, refer to Section 418-00 .
   • No response/not equipped for 4WD module (PCM), Go To Pinpoint Test G .
   • System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out the 4WD module (PCM) self test.

1. If the DTCs retrieved are related to the concern, go to the 4WD Control Module (PCM) Diagnostic Trouble Code (DTC) Index to continue diagnostics. 4WD Control Module (PCM) Diagnostic Trouble Code (DTC) Index
   DTC Description Source Action B1317 Battery Voltage HIGH 4WD Module (PCM) REFER to Section 414-00 . B1318 Battery Voltage LOW 4WD Module (PCM) REFER to Section 414-00 . B1319 Driver Door Ajar Circuit Failure 4WD Module (PCM) Go To Pinpoint Test M . B1322 Driver Door Ajar Circuit Short To Ground 4WD Module (PCM) Go To Pinpoint Test M . B1342 ECU is Defective 4WD Module (PCM) CLEAR the DTCs. REPEAT the 4x4 module (PCM) self test. If DTC B1342 is retrieved, INSTALL a new 4x4 module (PCM). REFER to Section 303-14 . CLEAR the DTCs. REPEAT the self test. B1483 Brake Pedal Input Circuit Failure 4WD Module (PCM) Go To Pinpoint Test M . B1485 Brake Pedal Input Short to Battery 4WD Module (PCM) Go To Pinpoint Test M . C1729 Transfer Case Unable to Transition Between 4H and 4L 4WD Module (PCM) Go To Pinpoint Test K . C1970 4WD Low Mode Switch LED Short to Battery 4WD Module (PCM) Go To Pinpoint Test K . C1971 4WD Low Mode Switch LED Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1707 Transfer Case NEUTRAL or PARK/NEUTRAL Indication Circuit 4WD Module (PCM) Go To Pinpoint Test M . P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1816 Transmission NEUTRAL Safety Switch Circuit Failure 4WD Module (PCM) Go To Pinpoint Test M . P1819 Transmission NEUTRAL Safety Switch Circuit Short to Ground 4WD Module (PCM) Go To Pinpoint Test M . P1820 Transfer Case Clockwise Shift Relay Coil Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1822 Transfer Case Clockwise Shift Relay Coil Circuit Short To Battery 4WD Module (PCM) Go To Pinpoint Test K . P1824 4-Wheel Drive Clutch Relay Circuit Failure 4WD Module (PCM) Go To Pinpoint Test H . P1826 4-Wheel Drive Low Clutch Relay Short Circuit to Battery 4WD Module (PCM) Go To Pinpoint Test H . P1827 4-Wheel Drive Low Clutch Relay Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test H . P1828 Transfer Case Counterclockwise Shift Relay Coil Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1830 Transfer Case Counterclockwise Shift Relay Coil Circuit Short To Battery 4WD Module (PCM) Go To Pinpoint Test K . P1849 Transfer Case Contact Plate A Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1853 Transfer Case Contact Plate B Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1857 Transfer Case Contact Plate C Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1861 Transfer Case Contact Plate D Short Circuit to Ground 4WD Module (PCM) Go To Pinpoint Test K . P1867 Transfer Case Contact Plate General Circuit Failure 4WD Module (PCM) Go To Pinpoint Test K . P1891 Transfer Case Contact Plate Ground Return Open Circuit 4WD Module (PCM) Go To Pinpoint Test K . U1900 CAN Communication BUS Fault 4WD Module (PCM) REFER to Section 418-00 . U2023 External Node Fault 4WD Module (PCM) REFER to Section 418-00 . U2051 One Or More Calibration Files Missing/Corrupt 4WD Module (PCM) Reprogram/Reflash the 4x4 module. REFER to Section 418-00 . - For All Other DTCs 4WD Module (PCM) REFER to Section 418-00 .
2. Your best bet mite be to take it to a qualified repair shop !