“Service Axle Locker System” Light On

MojitoJLUR

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Mine was in the shop for just over 30 days for the steering box.

Question for all about the sensor failure. Are these lights coming on only when you are using the lockers or can the warning pop up at anytime?

I don't use my lockers much since I live in the middle of a city with not many places to off-road. In fact I've only used them twice and that was when I first got the Jeep, like under 100 miles on it. First time I activated them, I had to make a sharp turn to avoid a tree and the "Service Axle Locker" notification came on in my gauge screen when I did. Got out of the woods, disengaged everything, re-engaged everything, and the message was gone. Just under 20K miles now and it hasn't come back on since, but I also haven't used my lockers since. Is my Jeep just waiting on me to use the lockers again so it can give me the warning?
The light will be on when it goes bad regardless if you have the lockers activated or not.
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SJSRubicon

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The light will be on when it goes bad regardless if you have the lockers activated or not.
I never used my lockers. I was at 2097 miles and less than 90 days owned. It came on suddenly for no reason while I was in 4L going up a short hill. It had to do with electrical sensors and the wiring harness. Articulating can sporadically cause it to come on and causes weight to shift back in forth which triggered the broken connection to break further. I videoed it all. The concern is there are some of us when it sporadically activated the lockers they were on the freeway, and that’s problematic safety wise. You don’t want your diff locking suddenly in 2H (which shouldn’t even be possible!) I had my lockers come on sitting still in 2H in the driveway having just pulled out of my garage; the shifting back and forth was enough to cause the connection to move and disconnect. Both of my axles were swapped out as well as the wiring harness. 21 days out of service not even 90 days old. Also had the 2021 steering box go bad too. Yes the redesigned 2021 steel steering box is bad too. Mine constantly drove to the right and wandered all over and was worse at freeway speed. It had a bad valve or as the mechanic put it there was a “bade valve” in the steering box. IDK did he mean bad valve or blade valve or really a bade valve. Never heard of a “bade” valve.
 

mackh4x0r

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I towed my camper on a long trip and now my service axle locker is on. They found oil in the sensor and replaced it. This fixed it for about a day and it came back on randomly the next day. I haven't told them yet. I was going to check the connections my self but I'm lazy.
 

SJSRubicon

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I towed my camper on a long trip and now my service axle locker is on. They found oil in the sensor and replaced it. This fixed it for about a day and it came back on randomly the next day. I haven't told them yet. I was going to check the connections my self but I'm lazy.
They had to replace both my axles and my wiring harness on my 2021 Rubicon. It’s was all three shorting out at 2097 miles of ownership. Go back to the dealer It’s not done being fixed yet. Mine got set off going up a short hill beginner level trail in 4H. I wasn’t even using my lockers. Took 21 days at the dealer. I notice with mine it particularly set it off when I jostled the jeep like forward reverse or my right front wheel articulating. I videoed it and it helped them to know where to look for the breaks in the electrical connection. I had never used my lockers when this happened.
 

mackh4x0r

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They had to replace both my axles and my wiring harness on my 2021 Rubicon. It’s was all three shorting out at 2097 miles of ownership. Go back to the dealer It’s not done being fixed yet. Mine got set off going up a short hill beginner level trail in 4H. I wasn’t even using my lockers. Took 21 days at the dealer. I notice with mine it particularly set it off when I jostled the jeep like forward reverse or my right front wheel articulating. I videoed it and it helped them to know where to look for the breaks in the electrical connection. I had never used my lockers when this happened.
That's crazy. My camper is just at or over 3500lbs... I thought maybe it was my fault, but maybe not totally. Mostly just a really bad design. I was hoping they redesigned it but I guess Jeep doesn't care.

Fingers crossed I don't have to wait forever to get it fixed. Right now I'm waiting on a leather replacement because the leather separated from the backseat levers... lol
 

mgroeger

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Well I have discovered there is yet another solution on the table. @chevymitchell has shown us how to pot the sensors before they fail and @wibornz has shown us how to harvest the sensor out of another axle. We all know FCAs bull$hit solution is to replace the entire axle... STILL AFTER 4 YEARS OF FAILURES. I went the route of Ted and harvested a sensor out of my wife's D44 axle we put on her Sahara. I did not pot that sensor but rather sealed the edges with silicon.
I got about a little over a year out of it and it failed. I looked at it this past weekend and I'm guessing oil got in through the wiring connector. I decided to put the original one back together and try it and voila... it worked!

What I did... I had taken the cover off of the original one a year ago when I took it out after it failed. I let the oil drain out and threw it in a box awaiting the day that aother failure would occur. I took some contact cleaner and some carb cleaner and sprayed it into the open sensor and let it soak for a min and dumped it out figuring what do I have to lose. I then hit it with some compressed air to blow it out and JB Welded the cover back on.

Since I was also doing a diff fluid change I had the front cover open and checked that sensor and it was in perfect working order. I took that sensor and did some resistance readings across the pins and son of a gun... the sensor I had cleaned and put back together had the same readings!! And as expected the sensor that was now failing didn't, so it would appear that it really is the oil that is causing all of the havoc, that the sensors themselves aren't failing.

I put the repaired sensor in the rear axle and took it for a spin and voila... works perfectly. The lockers engage INSTANTLY instead of taking their time and thinking like they start to do when they get oil in them. I put a thin bead of silicon around the tip of connector point on the sensor so that when the plug slipped over it created a seal where oil can't get into the plug. I also took some silicon and with my finger pressed it down into the holes where the two wires go into the connector from the wire harness side. I let that all sit for a day to cure up and it should keep the oil out. If it fails again I'll simply go the Z Harness route but the nerd and cheapo in me wanted to do it this way first.
 

chevymitchell

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The lockers engage INSTANTLY instead of taking their time and thinking like they start to do when they get oil in them.
Just a couple things. Lol.

Using carb cleaner on any electronic components is a surefire way to destroy any silicone part being used, so this test would need to be done and verified using only electrical cleaning components.

The instantaneous locking of the locker is great as long as the "in-transit" function of the sensor still works after cleaning it. If the "in-transit" function was damaged with the carb cleaner, then the cleaned sensor sounds like it will work like the Z-Harness does.

Thanks for the additional info. Did you say you potted this sensor or is still open to being shorted again? I will say that the oil is damaging the sensors as all of them I have tested have not been able to be brought back to life due to failed capacitators, but there is hope here. We'll see what happens as more people clean and re-assemble their sensors.
 

mgroeger

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Just a couple things. Lol.

Using carb cleaner on any electronic components is a surefire way to destroy any silicone part being used, so this test would need to be done and verified using only electrical cleaning components.

The instantaneous locking of the locker is great as long as the "in-transit" function of the sensor still works after cleaning it. If the "in-transit" function was damaged with the carb cleaner, then the cleaned sensor sounds like it will work like the Z-Harness does.

Thanks for the additional info. Did you say you potted this sensor or is still open to being shorted again? I will say that the oil is damaging the sensors as all of them I have tested have not been able to be brought back to life due to failed capacitators, but there is hope here. We'll see what happens as more people clean and re-assemble their sensors.
Good points!
Yep, I knew carb cleaner was technically a no no but I was in F-IT mode so figured I'd use it. MAS sensor cleaner might have been a safer bet and a little more aggressive than just contact cleaner to work against the gear oil.
That's a good point in that I didn't really test the repaired sensor in the real world yet... i.e. under load on an obstacle so I will have to report back on that when I get it out on a trail.
Technically I can't confirm the "in-transit" function, however I was getting the exact same resistance readings across the pins in both the front sensor that was in perfect working order and the repaired sensor so that gave me a warm fuzzy feeling.

At the end of the day I like the feeling of "sticking it to the man"... lol... I took their $hitty design and made it work again. I did not pot this sensor because didn't feel like ordering the stuff and doing it not knowing if my fix was going to work. If this one fails in the future I will most likely stop playing the FCA game and get the harness from Z Automotive and call it a day.
 

Yellow Cake Kid

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It seems like someday someone is going to order a batch of sensors from the actual sensor manufacturer and this issue will become a easy RnR procedure.
 

mgroeger

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It seems like someday someone is going to order a batch of sensors from the actual sensor manufacturer and this issue will become a easy RnR procedure.
Yeah, there have been multiple attempts at that and we keep getting denied.
 

chevymitchell

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Good points!
Yep, I knew carb cleaner was technically a no no but I was in F-IT mode so figured I'd use it. MAS sensor cleaner might have been a safer bet and a little more aggressive than just contact cleaner to work against the gear oil.
That's a good point in that I didn't really test the repaired sensor in the real world yet... i.e. under load on an obstacle so I will have to report back on that when I get it out on a trail.
Technically I can't confirm the "in-transit" function, however I was getting the exact same resistance readings across the pins in both the front sensor that was in perfect working order and the repaired sensor so that gave me a warm fuzzy feeling.

At the end of the day I like the feeling of "sticking it to the man"... lol... I took their $hitty design and made it work again. I did not pot this sensor because didn't feel like ordering the stuff and doing it not knowing if my fix was going to work. If this one fails in the future I will most likely stop playing the FCA game and get the harness from Z Automotive and call it a day.
There are 3 capacitors in the sensor and capacitors don't provide a straight resistance reading.

If the capacitor is good, it should read a low resistance and then slowly climb up to a high resistance short, eventually reaching an OL or infinite amount of resistance.

Hopefully it worked for you though. That would be really cool to have one brought back from the dead with a simple cleaning.
 

Jamrock

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Do we know which company makes the sensors?

Just so I understand properly... What exactly does the sensor monitor? Is there any risk in bypassing this monitoring activity?
 

Yellow Cake Kid

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There are 3 capacitors in the sensor...
You probably know this but it may be helpful for others etc.

Using an ohm meter is a sort of proxy measurement technique for capacitors. The two leads of the Capacitor are always open to direct current unless there is an internal short. The reason the ohm meter appears to initially see a low resistance is because the meter is temporarily energizing and charging the capacitor. The ohm meter is calibrated to interpret a flow of current and report a relative resistance value. As the capacitor charges and the current drops the resistance reading increases. Once the capacitor is charged the ohm meter reports the actual condition of an open circuit between the two sides of the cap.

A capacitance meter will measure ESR with an AC signal at some frequency, or a series of specific frequencies, which can give you some idea of the capacitance value of the component, but it is unlikely you will get an accurate measurement while the component is placed in a circuit where adjacent components affect the observed response.
 

mgroeger

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Do we know which company makes the sensors?

Just so I understand properly... What exactly does the sensor monitor? Is there any risk in bypassing this monitoring activity?
Someone found out who makes them but you can't buy them. The sensor is a hall sensor that monitors the state of the locker. Z Automotive (maker of the Tazer) has a harness you can buy for $75 which replaces the sensor and basically feeds a "everything is groovy" state back to the computer so you can engage and disengage the lockers without issue.
 
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