spear_11

bump help me out

TheJMC

Jack up and support the the front wheels so they are off the ground. Key on engage 4x4. Get under and try to turn the front driveshaft. If it doesn't turn the t-case is engaged. If it does turn the t-case is not engaged. if it doesn't turn and the 4x4 lights are not on the GEM dosn't know that the t-case is engages so it won't engage the front axle. Short the 4x4 solenoid closest to the passenger fender to ground. That should activate that solenoid and lock the front axle. Start the engine to provide vacuum to the system and try spinning the driver side front wheel. The passenger side should turn the opposite way if the axle is engaged. Post up the results.

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spear_11

how am i supposed to ground out the solenoid considering its in a closed connection?

TheJMC

1st option
Push a pin or a paperclip through the back side weather pak connector so it contacts the ground wire and run a wire from that to ground.

2nd option
Bare the insulation on the ground wire and run a wire from that to ground.

Regards

Jean Marc Chartier

spear_11

ok just so i do this right theres 2 wires that go into the engage side i put the pin in the ground and ground it somewhere else on the truck? and if this actuates 4x4 will i be able to get it out of 4x4 by switching to 2wd? and if it does go into 4x4 is the gem the problem

TheJMC

Did the front driveshaft turn or not? If it turned the front axle is a mute point.

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spear_11

if i put it in 4x4 with the backwheels on the ground it will not turn but if all the wheels off the ground i can turn the back wheels with the front driveshaft

carbon

I need to replace my GEM due to a crack in the upper drivers side windshield. This caused my 4x4 to stop working. Replaced all the vacuum lines, relays, fuses, transfer case 4x4 motor, vacuum solenoids and the vacuum actuator. I can maunally turn the transfer case into 4x4 and manually lock the front diff and it works perfectly. I am looking for a new GEM right now. Not saying this is your problem but ford had an issue with the GEM getting wet and corroding to cause electrical issues.

Here is some info I found that helped me track down my problem:

Pink vacuum line engages the 4x4
Blue vacuum line disengages the 4x4

What you need to do is measure the voltage at the connector
of the solenoid that has the pink line... Make sure there
is 12 volts there when you select 4X4. If it's working, then
check the pink line all the way to the axle actuator to make
sure it's not leaking or broken.

First off, check the 4WD fuse. That has to be working before you can
check out anything else. The two solenoids behind the battery are always
connected to battery voltage through the 4WD fuse, so there should always
be voltage on them. The 12V is fed to each solenoid through a white wire
with the light blue stripe. (W/LB)

There are relays built in to the GEM module (located above the fuse panel
above the driver's left knee). When you move the floor lever, or twist the
dash ****, you activate these relays built inside the GEM module. They will
ground one of the solenoids and un-ground the other. Grounding the solenoid
completes the circuit and causes it to provide vacuum. Un-grounding the
solenoid causes it to shut off the vacuum. The ground path for the 4WD
solenoid is via the red (R) wire.. The ground path for the 2WD solenoid
is via the grey wire with the black stripe (GY/BK) wire.

To check the operation of the GEM module, you can unplug the connector
and connect a 12 volt test light across the 12V terminal and the ground
terminal on the plug you just pulled off. The light will come on if the
GEM is providing a path to ground. Test each solenoid connector and make
sure the appropriate solenoid gets activated as you switch between 2WD
and 4WD. If the test light isn't coming on for one or both of the solenoids,
then suspect a faulty GEM module.

If they're working then you might have a vacuum problem. Make sure the vacuum
lines are all OK. Pull out the battery and make sure none of the lines got
crushed, cut or cracked by the last person who installed the battery. Also
check the vacuum reservoir. It's a thin black square thing with a vacuum line
going to it. It's fastened to the battery tray on the side closest to the fender.
As a note.. A bad leak in this area can cause the heater controls to malfunction
or not work 'quite right'.. If your heater controls aren't switching normally,
then pay close attention to the vacuum lines.

If the vacuum is OK, then you need to check the actuator. You need to take of
a plastic shield to see it. Watch the arm to make sure it's working.... If the
actuator is OK, then the lever system that disconnects the axles inside the
diff is not working. They do break from time to time. If that's the case, then
the front diff has to be pulled apart.

Look at the diagram of the actuator below and try visualize how the rod will
move depending on which side of the diaphragm is receiving vacuum. Vacuum from
the 4WD solenoid will push the rod out... Vacuum from the 2WD solenoid will
pull the rod in.

spear_11

ok im gonna try all these things this weekend and check everything over

rogerg

I have the same problem, however. I have power to the solenoid and vacuum, no vacuum from solenoid. I have no lights on the switch, but switch does work the motor on tranfer case.