Third Time’s Charmed

October 12, 2023 - Jeep-Jeep has not been well. Actually it’s suffering from a known problem with the model JL Jeep. But let me start at the beginning.

As we were returning from Utah in July 2022, a warning light on the dash started flashing and wouldn’t stop. We pulled over and got out the owner’s manual to find out what was wrong. It was a Saturday and the Jeep dealership closest to us was about to close. They took a quick look and said they couldn’t fix it then, but it was safe to drive. We drove home and did some online research. Apparently the rear-differential-locker sensor was in the process of failing. As long as the warning light is flashing, the sensor might still work, but it is just a matter of time until the light will stay illuminated. For those of you not familiar with a locker. I’ll explain, although I suspect I lost most of you a few sentences back. The rear differential (that big metal lump between the wheels) has a bunch of gears that direct power to the wheels but the wheel with the least resistance gets the most power. It also allows the wheels to turn at different speeds. That’s why it’s called a differential. That works great if you’re driving down the road and want to turn. If your driving off-road and one wheel has less resistance than the other it’s probably because its not on the ground or your stuck in loose gravel, mud, or sand.

Here we are in our off-road driving class. Yes, that back wheel is in the air.

If all the power goes to the wheel that’s off the ground, you aren’t going anywhere. To solve this problem, off-road vehicles can lock the two sides of an axle together so that both wheels receive the same power. That is unless the locker fails. Our locker didn’t fail. Only the sensor that allows the locker to engage. The locker engages electronically, meaning we push a button on the dash, which is easy and convenient. Mechanical lockers are better, as they don’t have delicate electronics in a dirty, hot, oil-filled location where they are subject to failure. But that’s a different vehicle.

On to my story. When we got home we called the local dealership. They couldn’t see us for a few weeks, but we kept driving and eventually the sensor light stopped flashing and just stayed lit, i.e. completely broken.

The sensor light flashes indicating the locker is trying to engage or disengage. If you try to use the locker while the light is flashing, it might work but it might not. If the light is just on, the vehicle thinks the locker is engaged, but in our case it’s a broken sensor. The locker never gets the signal to engage.

We took it in for service and were told it would be fixed under warranty but we would have to wait on parts. But to keep driving it. So we went to Arkansas. Not because we’re crazy, but because we had a trip scheduled and the mechanic also said it was OK to drive. Our trip went off without incident and we eventually got the sensor fixed.

For a while. Then it broke again, almost immediately. This time the mechanic said that it could be a different part and that it was their procedure to only replace one part at a time until they found the failed part. Thanks Jeep! That’s a nice policy. But they replaced another part under warranty and all was well, for a while.

Back to mechanics. The sensor that usually fails is in a little plastic box. (see below) When the gear oil heats up (think long trip, far from home, probably in the middle of nowhere) the oil can leak into the box and mess with the electronics. That’s a bad design. I don’t know what the other parts are but I hear there are two more.

Locker Sensor

I should remind you that this is a very common problem. When the light started flashing for the third time. I called my local Jeep dealership in my new town and told the service desk that I had “a 2021 Jeep Wrangler with a rear locker sensor failure and I need to bring it in for service”. He asked what was the problem. I repeated, “I have a Locker Sensor Failure.” He said, “Your check engine light is on?” … Clearly he didn’t know what a locker was. Maybe he was thinking of a place to keep his math book while he was in gym class.

When I dropping it off for service they said they were replacing several parts. When they called later in the day to say it was ready to be picked up, they also said it didn’t fix the problem. However, there was a new design available and at only 32,000 miles we had managed to squeak in just in time for the warranty to still be in effect. The warranty expires at 36,000 miles. If you are still reading, I’m impress. (Unless your Bob. Bob is thinking, “You should have bought a Bronco.”) The dealership said thirty days for parts.

At the time of posting this blog we have been waiting 38 days. I’ll call again on Monday.

In the mean time this orange light is still flashing.

So is this one.

The part we are waiting on is a new re-designed differential. We hope it’s not just re-designed to fix one problem but create another! It will be under warranty for another 2 years or 36,000 miles. If you want to know more about how the sensor fails and what to do if its not under warranty, Jeepers have a hack. Check out this post. In the mean time we’re still driving it.

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