06 Rubicon lockers not working

Chapman4266

Chapman4266

TJ Enthusiast
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Joined
Mar 2, 2019
Messages
336
Location
Snyder TX
I have an 06 Rubicon just purchased. In 4L, sitting still, when switch is pushed down, no dash light and no switch light. I don’t have anywhere local I can get on 3 wheels to see if it is working or not. The compressor is there and all air lines look good. I’m aware of defeating The factory wiring, but the way it works by the factory is fine for me. I just want it all to work like it should. Any ideas? Should I be able to have someone push the switch and hear or feel the compressor running from under it? This is my first Jeep. Like I said, I’m just trying to get it to work like it should. Thanks for any help you can give.
 
Has to be in 4 lo if wired stock,and rolling slow . s-turns help. Yes the compressors can be heard.

The switch is a momentary . One click locks the rear , 2nd click the front .

See if that helps and let us know .

Check fuses too.
 
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You won't hurt anything if you lock the axles on pavement. Find an open parking lot and go slow. See what happens.
 
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Another thing to do is to switch to 4L, turn the engine off and back into the on position. Don't start the engine, you want quiet. Turn on the locker pumps and listen for a couple seconds of fish tank air pump sound.

I trust that you have crawled under the Jeep and laid hands on the pumps on the back side of the skid plate.
 
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I haven’t laid hands on them while trying to activate them. I replaced a u joint today and inspected all the air lines and wiring. It all looks factory. Just not familiar with factory lockers or any others for that matter.
 
Chapman4266 said:
I haven’t laid hands on them while trying to activate them. I replaced a u joint today and inspected all the air lines and wiring. It all looks factory. Just not familiar with factory lockers or any others for that matter.
Click to expand...
At least they exist! ;)
 
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Chapman4266 said:
I have an 06 Rubicon just purchased. In 4L, sitting still, when switch is pushed down, no dash light and no switch light. I don’t have anywhere local I can get on 3 wheels to see if it is working or not. The compressor is there and all air lines look good. I’m aware of defeating The factory wiring, but the way it works by the factory is fine for me. I just want it all to work like it should. Any ideas? Should I be able to have someone push the switch and hear or feel the compressor running from under it? This is my first Jeep. Like I said, I’m just trying to get it to work like it should. Thanks for any help you can give.
Click to expand...
I strongly suspect if you look at your PCM, you will find a reman sticker on it somewhere. The 4wd dash light has to be illuminated first before the PCM will send power to the switch on the dash to allow the pumps to be switched on to pump air to the locker(s).

If the dash light does not come on in 4 low, then the first thing to check after verifying the PCM is correct is the mode switch on top of the t-case. It is a 4 position resistance based switch that tells the PCM which mode the t-case is in and allows certain functions to occur based on the mode specifics.

You can check the resistance values of each mode based on the specs in the FSM. Or you can swap it with a known good one. I find very few of them to be bad and typically this issue is based on a reman PCM with the wrong software in it for the Rubicon specific application.

A few things of note. No, you do not have to be rolling for the light to turn on and flash and then go solid to indicate it is locked. If the locker is lined up to be able to be locked sitting still, it will lock and go solid at the light. The movement is only need to achieve differentiation between the two tires to line it up if it isn't locked.
 
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jjvw said:
Moving or not, the lights ought to flash once the switch has been activated, then go solid once locked.
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Turned key on with trip pressed. Ran through all lights and gauges. The 4wd light lit up, but front and rear lock lights did not. Fuses good. Swapped a couple relays, but made no difference. Turned key on and off several times while in 4L and kept trying to hear compressor, but heard nothing.
 
mrblaine said:
I strongly suspect if you look at your PCM, you will find a reman sticker on it somewhere. The 4wd dash light has to be illuminated first before the PCM will send power to the switch on the dash to allow the pumps to be switched on to pump air to the locker(s).

If the dash light does not come on in 4 low, then the first thing to check after verifying the PCM is correct is the mode switch on top of the t-case. It is a 4 position resistance based switch that tells the PCM which mode the t-case is in and allows certain functions to occur based on the mode specifics.

You can check the resistance values of each mode based on the specs in the FSM. Or you can swap it with a known good one. I find very few of them to be bad and typically this issue is based on a reman PCM with the wrong software in it for the Rubicon specific application.

A few things of note. No, you do not have to be rolling for the light to turn on and flash and then go solid to indicate it is locked. If the locker is lined up to be able to be locked sitting still, it will lock and go solid at the light. The movement is only need to achieve differentiation between the two tires to line it up if it isn't locked.
Click to expand...
Can the pcm be updated with correct software?
 
Chapman4266 said:
Turned key on with trip pressed. Ran through all lights and gauges. The 4wd light lit up, but front and rear lock lights did not. Fuses good. Swapped a couple relays, but made no difference. Turned key on and off several times while in 4L and kept trying to hear compressor, but heard nothing.
Click to expand...
You have to start with the first step which is making the dash light 4WD light up in 4 low. Until that happens, nothing else related to making the switch work will occur.
 
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Chapman4266 said:
The 4wd light is not coming on. I will check pcm and go from there when it’s daylight again. Thank you for helping.
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Hopefully it is the mode switch on the t-case. The bypass to allow the lockers to function in all modes will solve the issue. I don't do that because I prefer the system to work like it should.
 
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