Locker Position Sensor Potting - DANA 44

[chevymitchell]

New to me jeep JL 2022 Rubicon 4 door. All was ok when we picked her up but as soon as we hit the highway doing about 60mph/100kmph the rocker light flashes on the dash and the switch. It was intermittent the first few days. Then it disappeared and now appeared again.
I have ordered a new sensor from eBay but it will take a few weeks before it crawls back to india.
Question is:
Can the old sensor still be saved?
Since it comes and goes does it mean it still has some life left and if I clean it and pot it chances are it will work?

But what a beautiful thread.

If it hasn’t failed completely, then there’s a chance you’ve caught it in time. Take the time to pot them and see.

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[LukeDagny]

If it hasn’t failed completely, then there’s a chance you’ve caught it in time. Take the time to pot them and see.

Just to clarify in my mind. The sensor just tells you if the differential is locked or not. With a bad sensor, the locker will still work, you just have the annoying warning light?

 

[chevymitchell]

Just to clarify in my mind. The sensor just tells you if the differential is locked or not. With a bad sensor, the locker will still work, you just have the annoying warning light?

No, with a bad sensor, the module will remove the locker from being used.

The sensor doesn't just function as a position indication, it also provides an "in-transit" function.

A bad sensor can inadvertently lock the locker without selecting it up front, as well.

Best to get it cleaned and potted or replaced. You can bypass if you want but you will lose the flashing "in-transit" function.

 

[LukeDagny]

No, with a bad sensor, the module will remove the locker from being used.

The sensor doesn't just function as a position indication, it also provides an "in-transit" function.

A bad sensor can inadvertently lock the locker without selecting it up front, as well.

Best to get it cleaned and potted or replaced. You can bypass if you want but you will lose the flashing "in-transit" function.

Thanks. I guess I "dodged a bullet". I drove around for several weeks with the light on before I replaced my sensor with one that was potted.

 

[grimmjeeper]

No, with a bad sensor, the module will remove the locker from being used.

The sensor doesn't just function as a position indication, it also provides an "in-transit" function.

A bad sensor can inadvertently lock the locker without selecting it up front, as well.

Best to get it cleaned and potted or replaced. You can bypass if you want but you will lose the flashing "in-transit" function.

The sensor is just a binary on-off switch.

The in transit function is all in the computer. The locker starts "off". You hit the button and it flashes, "in transit" if you will, until the locker sensor changes to "on". Then the light stops blinking.

The same happens in reverse when you unlock. You hit the button and the light flashes until the sensor switches over to "off".

There is a time limit for the sensor to flip. If it doesn't flip in time, the computer will complain with a Service Locker notice. And if the rear is the one that doesn't register that it's locked, the computer won't let you lock the front.

Also, if the switch suddenly shorts out wen you're not locked, the computer will freak out on you.

 

[ym0bc1]

Thanks. I guess I "dodged a bullet". I drove around for several weeks with the light on before I replaced my sensor with one that was potted.

See my post
https://www.jlwranglerforums.com/fo...y-not-all-caused-by-bad-locker-sensor.160732/

It started to have problem after i potted the sensor. My conclusion is that the factory set up is not precisely aligned. Once removing/reinstall, there may be a slight difference. All you need is to move around to find the proper alignment.

 

[ym0bc1]

The sensor is just a binary on-off switch.

The in transit function is all in the computer. The locker starts "off". You hit the button and it flashes, "in transit" if you will, until the locker sensor changes to "on". Then the light stops blinking.

The same happens in reverse when you unlock. You hit the button and the light flashes until the sensor switches over to "off".

There is a time limit for the sensor to flip. If it doesn't flip in time, the computer will complain with a Service Locker notice. And if the rear is the one that doesn't register that it's locked, the computer won't let you lock the front.

Also, if the switch suddenly shorts out wen you're not locked, the computer will freak out on you.

Thanks for the explanation. I see some posts saying about some scenarios:
* locker stuck at ON position. I'm not sure if this is just a false status, or it's physically stuck. If we shut off the engine, would the sensor back to unlock?
* locker inadvertently engage without pushing the button - not sure how this could happen.

 

[grimmjeeper]

Thanks for the explanation. I see some posts saying about some scenarios:
* locker stuck at ON position. I'm not sure if this is just a false status, or it's physically stuck. If we shut off the engine, would the sensor back to unlock?
* locker inadvertently engage without pushing the button - not sure how this could happen.

The sensor attaches to the locker and it tries to tell the computer when the mechanism locks.

Most of the time, the problem is in the sensor. It fails way more often than the locker itself. It can fail either way. It can fail to detect the locker locking or it can give a flase positive when the locker is not locked.

It is possible for the locker itself to fail but most failure modes cause it to stay unlocked.

 

[chevymitchell]

The sensor is just a binary on-off switch.

The in transit function is all in the computer. The locker starts "off". You hit the button and it flashes, "in transit" if you will, until the locker sensor changes to "on". Then the light stops blinking.

The same happens in reverse when you unlock. You hit the button and the light flashes until the sensor switches over to "off".

There is a time limit for the sensor to flip. If it doesn't flip in time, the computer will complain with a Service Locker notice. And if the rear is the one that doesn't register that it's locked, the computer won't let you lock the front.

Also, if the switch suddenly shorts out wen you're not locked, the computer will freak out on you.

It’s not binary, unfortunately, like the JK.

It provides the in transit function as mA’s on the signal line to the module. Then there’s a debounce time for after it’s fully engaged or disengaged. Then it’ll throw the failure unless it’s just shorted or open.

You can sit with the plate partially engaged and the blinking for a very long time without failure. I tested this when I built my own bypass harness.

It can inadvertently lock by the sensor shorting to the lock position. The module doesn’t need the switch hit to lock if the sensor shorts out. @mgroeger has had this happen in a drive thru. Then the only way to unlock it is to unplug it and the magnet will de-energize.

 

[chevymitchell]

The sensor attaches to the locker and it tries to tell the computer when the mechanism locks.

Most of the time, the problem is in the sensor. It fails way more often than the locker itself. It can fail either way. It can fail to detect the locker locking or it can give a flase positive when the locker is not locked.

It is possible for the locker itself to fail but most failure modes cause it to stay unlocked.

For sure. It’s designed to fail unlocked, as it should be. I like being able to simply unplug it to just remove (most) all the variables.

 

[grimmjeeper]

It’s not binary, unfortunately, like the JK.

It provides the in transit function as mA’s on the signal line to the module. Then there’s a debounce time for after it’s fully engaged or disengaged. Then it’ll throw the failure unless it’s just shorted or open.

You can sit with the plate partially engaged and the blinking for a very long time without failure. I tested this when I built my own bypass harness.

It can inadvertently lock by the sensor shorting to the lock position. The module doesn’t need the switch hit to lock if the sensor shorts out. @mgroeger has had this happen in a drive thru. Then the only way to unlock it is to unplug it and the magnet will de-energize.

I missed seeing that bit of information. Thanks for correcting me.

 

[chevymitchell]

I missed seeing that bit of information. Thanks for correcting me.

It’s all good man. This stuff is so over engineered. lol. It really should just be a switch or discreet. Everything would be so much simpler.

…except for the warranty claims for people hammering on the gas after their locker light goes out and it’s truly not unlocked. lol! Awww… snap.

 

[ym0bc1]

It’s not binary, unfortunately, like the JK.

It provides the in transit function as mA’s on the signal line to the module. Then there’s a debounce time for after it’s fully engaged or disengaged. Then it’ll throw the failure unless it’s just shorted or open.

You can sit with the plate partially engaged and the blinking for a very long time without failure. I tested this when I built my own bypass harness.

It can inadvertently lock by the sensor shorting to the lock position. The module doesn’t need the switch hit to lock if the sensor shorts out. @mgroeger has had this happen in a drive thru. Then the only way to unlock it is to unplug it and the magnet will de-energize.

Shawn, thanks. Could you elaborate how the "inadvertently lock" happens? I'm also trying to nderstand this better and modify the sensor's PCB (got some spare to play with) to make it last. The MLC capacity on it is not rated for high temperature operation. It will most likely to fail after at 5K ops hrs.

 

[chevymitchell]

Shawn, thanks. Could you elaborate how the "inadvertently lock" happens? I'm also trying to nderstand this better and modify the sensor's PCB (got some spare to play with) to make it last. The MLC capacity on it is not rated for high temperature operation. It will most likely to fail after at 5K ops hrs.

Most MLC’s fall under Class I. I can’t remember the range but it’s usually around -45/50 C to +110/120 C or so. You’d really have to bake the sensor in an over temp’d diff to hurt it, I think; with temp anyway.

Inadvertant happens when the magnet wiring is shorted by the metal particles in the oil. This can happen in the bulkhead connector or the magnet itself. In the sensor, if the module reads a locked condition, it will cycle through a test condition where it tries to engage and disengage very quickly. When it tries to do this, it’ll just stay locked. I was only able to duplicate this one time and then @mgroeger actually experienced it in the real world which confirmed it for me.

 

[chevymitchell]

Shawn, thanks. Could you elaborate how the "inadvertently lock" happens? I'm also trying to nderstand this better and modify the sensor's PCB (got some spare to play with) to make it last. The MLC capacity on it is not rated for high temperature operation. It will most likely to fail after at 5K ops hrs.

Too bad we can’t have access to the ICD or SYRD. I imagine the MTBF for it is in the thousands and thousands of hours but all that’s for not once you bathe it in metallic particle contaminated oil. lol. I don’t think they planned on that failure to happen.

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