Independent Rubicon Locker Switches
Independent control of the Front and Rear Lockers is accomplished by adding 2 Single Pole, Single Throw (SPST) switches, some jumper wires, and connectors to the existing Axle Lock Switch and/or wiring located in the center console. As with most electrical installations, the first thing that should be done is to disconnect the battery’s negative terminal connection from the battery.
Inside the TJ’s cockpit, gently pull back and up on the defroster ventilation panel located between the windshield and dash. It should easily unsnap without much effort.
Once the vent is out of the way, you will see two ¼” Hex/Phillips head screws located on the top of the center console. Remove these and then gently pull the center console facade straight out and upward – it is held in place by 4 spring clips so hold the top and bottom when performing this task.
Once the console façade has been removed, remove the four ¼” Hex/Phillips head screws holding the switch panel in place. Pull the switch panel out and you will now have access to the connections needed to accomplish this modification.
The schematic shows the electrical connections that need to be made for this modification. The switches I used are from AutoZone. The manufacturer is Pilot, the P/N is PL-SW26, and the type is Racing Switch with Safety Cover – about $10.00 each. I put both switches in the vacant Passenger Air Bag On/Off switch area.
Connect a jumper wire from Pin 1, or the BK Wire, located on the back of the Axle Lock Switch to the same contact on both switches. Then connect a jumper wire from the other contact on the Front Locker Switch to Pin 7, or the VT/DB Wire. The remaining Switch will control the Rear Locker, so connect a jumper wire from the remaining switch contact to Pin 6, or VT/LG wire. This completes the modification.
Connect the negative battery terminal back to the battery and test. Insert the key into the ignition and turn on one of the switches. You should hear the pump engage and then turn off as well as well see the dash indicator light flashing or in steady on state. Turn the switch off and the light should extinguish. Test the other switch. If everything looks good, put everything back together in the reverse of taking it apart.
Theory of Operation
(See section 8W-31-12, 13, 14, and 15, and 8W-80-5 of the FSM)
Since the Relays always have power applied to the D4 and D13 connection, applying a ground to D6 or D11 will cause the Rear and Front Locker Relay to energize, respectively. Once energized, voltage will be supplied to the Rear or Front Locker Pumps. They will turn on until 5 PSI of pressure is achieved, and then the pump will turn off – assuming no air leaks.
The two switches basically bypass the existing Axle Lock Switch and control the Front and Rear Locker Relays independently, as well as sending a Logic “0” to the Instrument Cluster (EMIC). The Front and Rear Locker Indicator lamps function exactly the same as originally designed: slow flashing when lockers are engaged without the axles actually being locked, and steady on when the lockers are fully locked and have sent an additional ground signal to the EMIC.
Two important things to recognize about this modification:
1. The switches bypass all safety interlocks, so the lockers can be engaged at any speed, and in any transfer case setting, and will almost certainly not disengage when going over 45 mph.
2. The Locker Relays always have voltage applied to them, even when the key is out, so the switches must be returned to the open position when not in use. If not returned to the Off position, then there is a possibly of running the battery down if there is a leak in the air lines and the pumps continue to cycle, and/or damaging the pumps.