Front locker won't engage

4x4Weapon

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Joined
May 17, 2020
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15
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Canada
Hey guys I have a 2004 TJ rubicon and the front locker won’t engage. My rear locker engages and is actually locked in, but both lights on the cluster flash indicating both are not locked. I found today that the wire going to the sensor on the rear axle is not telling the computer she is locked being the reason for the flashing light. Do the jeep have to recognize that the rear is locked (light solid) before it will allow the front to lock??
 
K I got one other question. The wire running to the rear axle is there and in tact. But at the back of the plug in, there are wires that are chopped. I am assuming they are the wires that used to run back to the computer? Or instrument cluster? Any idea where these wires run? Could they still be hanging there somewhere and I don’t see them? Like by the rear bumper or something?
 
Did you download the FSM? Read up on the logic behind the lockers. Much easier to diagnose if you understand how it was designed to operate. Note: EMIC (electromechanical instrument cluster).
370AEBC4-546D-41CF-9D16-94926C985E78.jpeg
 
Awesome thank you Daryl. I found the problem. The plug at the top of my axle has a wire that runs to the sensor in the axle, well this wire is completely missing. I can buy another sensor and replace, but I am pretty sure to correctly replace the sensor the carrier and axles have to be removed. Bit bigger of a job then I had hoped for but hopefully YouTube will have some videos lol thank you
 
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Awesome thank you Daryl. I found the problem. The plug at the top of my axle has a wire that runs to the sensor in the axle, well this wire is completely missing. I can buy another sensor and replace, but I am pretty sure to correctly replace the sensor the carrier and axles have to be removed. Bit bigger of a job then I had hoped for but hopefully YouTube will have some videos lol thank you

It really isn't that hard at all if you have a descent socket set and torque wrench. I'm no master mechanic and I did it. One word of advice, make sure you mark the shims that are on either side of the carrier when they come out. If you get those back in opposite of what they came out, its probably gonna mess up your diff clearances. Also be mindful that if you pull the carrier, the shims may fall out while you are removing the carrier.

Grab a 6 pack and put on some music. It won't be one of those knuckle busting events
 
Ok awesome I see in some forums people say the axle has to be hauled for the carrier to come out.. anyone know if that’s correct?
 
Ok awesome I see in some forums people say the axle has to be hauled for the carrier to come out.. anyone know if that’s correct?
Axle shafts have to be removed but the axles can remain in place.

My Rubicon lockers wouldn't work when I bought it due to wiring issues. It was quicker and easier to rewire them using simple on-off switches so no sensors are required. The compressors work automatically to shut on & off as required, just replace the OE switch with a pair of simple SPST switches to control the switches.

This is how mine turned out, I no longer use the factory locker switch for anything.

Locker Switches 2.JPG
 
Be aware there's a bit of a technique/trick involved to get the carrier back in if that sensor is in place. The sensor will get positioned onto the wrong side of the locker actuator and cause the locker to be partially engaged.

If you try to get the carrier back into place without knowing how you're in for some major frustration. Basically it involves holding the sensor open further than it normally sits until the carrier is back in place, then releasing it to go to its normal correct position.

Revolution Gear told me about the problem when I was regearing my axles and told me about the toothpick technique. Pull the sensor out all the way, then insert a piece of toothpick with a piece of fishing line tied to it cut to the right length to hold the sensor out fully extended. Then mount the carrier, then pull the fishing line to pull the toothpick out to release the sensor to its normal position.

Sensor pin.jpg
Toothpick-in-Sensor.jpg


But if you decide to rewire your locker compressors using on-off switches you don't need to install the sensor or use the above technque.
 
Yes in my searching of the site I have found this write up here it is very informative and important thank you Jerry. I was gonna replace the air vent nipple while I was in there but they are 97 bucks for the dealer and 41 bucks on summit. Also the locker sensor is 182 bucks canadian at the dealer and 76 bucks on summit. Is there any reason to go OEM here or are the Mopar parts at summit fine?

Thanks again for the help love this site
 
Yes in my searching of the site I have found this write up here it is very informative and important thank you Jerry. I was gonna replace the air vent nipple while I was in there but they are 97 bucks for the dealer and 41 bucks on summit. Also the locker sensor is 182 bucks canadian at the dealer and 76 bucks on summit. Is there any reason to go OEM here or are the Mopar parts at summit fine?

Thanks again for the help love this site
If you can stand the locker light(s) flashing while the locker is engaged you don't need that sensor. I eventually removed mine after rewiring the locker compressors to use my on-off switches. But if you want them to work like the lawyers at Jeep insisted, I'd use the Summit sensor without a second thought.
 
Ok the only reason I am replacing the sensor is because my front locker won’t lock, and I was told that if the rear doesn’t lock, (or if the Light in the cluster doesn’t go solid) then the front locker won’t lock? Is this true? I was hoping fixing the sensor could be the reason my front ain’t locking up?
 
If you can stand the locker light(s) flashing while the locker is engaged you don't need that sensor. I eventually removed mine after rewiring the locker compressors to use my on-off switches. But if you want them to work like the lawyers at Jeep insisted, I'd use the Summit sensor without a second thought.

Ok the only reason I am replacing the sensor is because my front locker won’t lock, and I was told that if the rear doesn’t lock, (or if the Light in the cluster doesn’t go solid) then the front locker won’t lock? Is this true? I was hoping fixing the sensor could be the reason my front ain’t locking up?
 
Ok the only reason I am replacing the sensor is because my front locker won’t lock, and I was told that if the rear doesn’t lock, (or if the Light in the cluster doesn’t go solid) then the front locker won’t lock? Is this true? I was hoping fixing the sensor could be the reason my front ain’t locking up?
What you are saying is true for the factory wiring setup.

What Jerry is saying is that if you directly wire it like his setup, you can lock the front and rear independently.

Jerry's way is simpler and more desirable since you can control front and rear independently.
 
K so here is what I have found:

both lights Flash.
Both compressors are working
both sensor wires are broke right at the sensor (no room to splice)

Only the rear locks.

I ain’t going at hauling both carriers so I will live with the flashing lights.

if I do what Jerry has done is it just to splice into the wires behind the dash and add some switches?

this is what I found online and I am wondering if this is the route Jerry took?

http://www.wanderingtrail.com/Mods/TJLJmods/Locker_Defeat.htm