I had the control module disconnected will my 4WD still work on my jeep.

Inside the ECM/PCM. Dodge,Chrysler, and Jeep. Used to have separate TCM's. But now the integrated in to the power train control module. PCM. what is your problem?

When the 4WD lights flash on and off, this indicates that there are 4WD-related trouble codes in the 4WD control module. Sometimes 4WD lights never illuminate.
The first step in diagnosing the system is to establish communication and retrieve trouble codes from the control module. After retrieving the codes, write them down, clear the codes and retest to see which codes are regenerated. False codes can be set if a component is disconnected when the key is turned on.
If the 4WD lights flash on and off, and no codes are found in the 4WD control module, try clearing the codes anyway. After a certain amount of key cycles, the codes will normally clear from the 4WD control module, but the module will not respond to commands until it is re-initialized by clearing the codes or disconnecting the battery to erase its memory.
If your scan tool will not communicate with the 4WD module, first verify that the scan tool has the proper software and the latest updates. If it does, then try another scan tool. If it still has no communication, the power and grounds that are supplied to the module will need to be tested. See if the scan tool will communicate with the other modules on the shared communication network. If they're OK, check the harness from the data link connector (DLC) for an open circuit to the 4WD module.

first check fuses,relays, and power connections -if good than check the control module for the 4wd check connections and for power ,next check the transfer case look at the actuator and casing for damage and or disconnected wires if u can use a rubber mallet do not hit with metal hammer [can damage crack housing] tap around actuator sometimes rod sticks a light tap makes it move gear out of 4wd

What large square fuse ? The 4X4 switch get's it's B+ voltage from the four - wheel drive control module . computer controlled ! Has two relay's - transfercase hi to low & low to high ,located in the Auxiliary relay box #3 . location left side of radiator core support . Your best bet ,take it to a qualified repair shop that has a diagnostic tool that can communicate with the 4X4 control module . Read code's ! Probably has a code like one of these
P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure 4WD control module Go To Pinpoint Test D . P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground 4WD control module Go To Pinpoint Test A .
But code have a few others as well .
B2105 Throttle Position Input Out of Range Low 4WD control module Go To Pinpoint Test B . B2106 Throttle Position Input Out of Range High 4WD control module Go To Pinpoint Test B . C1728 Transfer Case Unable to Transition Between 2H and 4H. 4WD control module Go To Pinpoint Test C . C1729 Transfer Case Unable to Transition Between 4WD HIGH and 4WD LOW 4WD control module Go To Pinpoint Test D . C1979 IWE Solenoid Circuit Failure 4WD control module Go To Pinpoint Test F . C1980 IWE Solenoid Short to Battery 4WD control module Go To Pinpoint Test F . P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure 4WD control module Go To Pinpoint Test D . P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground 4WD control module Go To Pinpoint Test A . P1824 Transmission 4-Wheel Drive Clutch Relay Circuit Failure 4WD control module Go To Pinpoint Test A . P1826 Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Battery 4WD control module Go To Pinpoint Test A . P1827 Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Ground 4WD control module Go To Pinpoint Test A . P1849 Transmission Transfer Case Contact Plate A Short Circuit to Ground 4WD control module Go To Pinpoint Test D . P1853 Transmission Transfer Case Contact Plate B Short Circuit to Ground 4WD control module Go To Pinpoint Test D . P1857 Transmission Transfer Case Contact Plate C Short Circuit to Ground 4WD control module Go To Pinpoint Test D . P1861 Transmission Transfer Case Contact Plate D Short Circuit to Ground 4WD control module Go To Pinpoint Test D . P1867 Transmission Transfer Case Contact Plate General Circuit Failure 4WD control module Go To Pinpoint Test D . P1891 Transmission Transfer Case Contact Plate Ground Return Open Circuit 4WD control module Go To Pinpoint Test D .

I would say someone has disconnected it rather than fix it.
You might find a missing fuse or relay that powers the ABS module, or the module may be unplugged. It could have been removed too.

There is a common problem with false "service 4WD" messages. The PCM or FDCM (final drive control module) may need to be updated. Also make sure that when you switch into 4WD, it is ACTUALLY IN 4WD. If everything appears to be working correctly, but there is still a message, there is one thing you can try:
You can check the transfer case actuator connector. It is the only electrical connector on the transfer case and is located underneath the center of the vehicle towards the driver side. Disconnect it (Carefully! The connector here has a tendency to seize into place. You don't want to break it or the tabs.) and check the wiring for dirt and debris around the connector. Also check for corrosion (green or white crusty stuff) on the metal connector terminals.
One other problem I have encountered was the axle shift solenoid in the front differential. The wires were broken inside the differential assembly. However, in this case the 4WD system was not functioning properly.

So, your question being what usually needs to be serviced, the answer is one or more control modules probably need to be flashed (updated). This obviously requires you to go to a dealership. However, you can visually check your transfer case connector to see if there are any potential wiring issues involved. Again, BE CAREFUL when disconnecting and reconnecting this component.

Hope this helps!

The main control module is the most sensitive, but you should go through the motions of checking if there is spark, if there is fuel pressure, etc. The control module is expensive. But you can try a salvage yard one.

When the 4WD lights flash on and off, this indicates that there are 4WD-related trouble codes in the 4WD control module. Sometimes 4WD lights never illuminate.
The first step in diagnosing the system is to establish communication and retrieve trouble codes from the control module. After retrieving the codes, write them down, clear the codes and retest to see which codes are regenerated. False codes can be set if a component is disconnected when the key is turned on.
If the 4WD lights flash on and off, and no codes are found in the 4WD control module, try clearing the codes anyway. After a certain amount of key cycles, the codes will normally clear from the 4WD control module, but the module will not respond to commands until it is re-initialized by clearing the codes or disconnecting the battery to erase its memory.
If your scan tool will not communicate with the 4WD module, first verify that the scan tool has the proper software and the latest updates. If it does, then try another scan tool. If it still has no communication, the power and grounds that are supplied to the module will need to be tested. See if the scan tool will communicate with the other modules on the shared communication network. If they're OK, check the harness from the data link connector (DLC) for an open circuit to the 4WD module.

It sounds like someone has changed into 4wd at speed and broken the internals of the system. Check the relays and fuses first but it sounds more serious than that. If it drives in 2wd put it in reverse an circle listen for any undue noises.

1. Remove the IP trim bezel.
2. Pull out the lamp switch, 4WD shift buttons, cargo lamp and air deflector louver assembly in order to disconnect the electrical connectors.
3. Disconnect all the electrical connectors from the lamp switch, cargo lamp and 4WD shift buttons assembly.
4. Remove the lamp switch, 4WD shift buttons, cargo lamp and air deflector louver assembly from the vehicle
5. Remove the electrical harness retainer from the IP support beam.
6. Disconnect the 2 electrical connectors from the transfer case shift control module.
7. Move the electrical harness to the left side in order to make room to turn the transfer case shift control module.
8. Rotate the transfer case shift control module about 45 degrees counter clockwise while pulling out at the same time until the module is approximately 90 degrees from the original position.
9. Pull out the module from the vehicle