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JLUR battery flatlining when flat towing

JimN

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If you want the Connect system to continue to run, then it will eventually run down your battery. In this case, it seems to me that putting a charger on it would be best,
Not sure I understand. I shut the Jeep OFF, nothing should be on when I tow. The Ignition is in the OFF setting. However, apparently the darned thing 'Wakes Up' every time you hit the brakes! This is a drain and over 6 hundred mile two is apparently enough to kill the battery. Perhaps there are other issues that also cause a 'wake up. Anyway, right now I just ran a Charge line with a DIode, I was looking at the RVi toad Charger, but it requires a very expensive monitor to see what it is doing, FIne I suppose if you are also buying their TPMS as it is the same monitor, but no good if you are already covered in that area. If they made it so it would read to Blue Tooth I'd have done it, but apparently they decided to lock up the signal with encryption.I suppose I'll fine out this week. We have a several hour tow. I think I'll grab my meter and check the voltage when we start out and when we arrive, although with the charge line it should be fine and I don't want to take the batteries down again.
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JimN,

I think you are spot-on in isolating what the problem is. The JL's enter a sleep-state about 3 minutes after the last door is closed. As mentioned previously, you can easily validate this by closing the driver's door and leaving the window down. After ~3 minutes you can stick a broom handle in through the open window and depress the brake pedal - and NO brake lights SHOULD activate. The Jeep is "asleep" and not drawing any power.

You said that you tried this broomstick test and the brake lights work, even though you let the Jeep sit a few minutes after closing the last door. THIS IS A PROBLEM. Your Jeep HAS to go into a sleep state or it will continue to draw power. I would recommend you to try the broom-stick test again. To be safe, wait 10 minutes after the last door is closed before pressing the brake pedal.

I am biased, but I am not a fan at all of the outdated and old-fashioned, diode-based towed wiring harnesses. I guarantee that all these companies did was to send updated electrical plug configuration specs to their China-based manufacturers and they sent over the same, 20-year old diode-based system design... and crossed their fingers. Not one of them has likely noticed an extra, fault-sense indicator wire in the tail light wiring harness - let alone know what it is for. Duh!

For readers here, the reason is that for the last 20+ years it has been rather easy to detect a bulb-out fault condition with a conventional light bulb. The system simply looks for the resistance across the filament. If this resistance goes to an open circuit condition, then the light is out (filament is broken). This method doesn't work for LED lights. Additional, non-trivial circuitry has been added to detect bulb-out conditions with LED lights. So, when you purchase that 20-year old, diode-based circuitry (albeit with new plugs that fit your Jeep), do you think they are properly isolating the fault-sense circuitry? I'm not saying with any confidence that this is the problem here - but we've heard plenty of strange stories of lights flashing and horns honking when connecting/disconnecting some of these antiquated, diode-based harnesses. In brief, buy the MOPAR harness (they know what they are doing) or buy our harness (complete physical isolation without diodes) and eliminate these possibilities. Sorry, rant over.
 

JimN

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JimN,

I think you are spot-on in isolating what the problem is. The JL's enter a sleep-state about 3 minutes after the last door is closed. As mentioned previously, you can easily validate this by closing the driver's door and leaving the window down. After ~3 minutes you can stick a broom handle in through the open window and depress the brake pedal - and NO brake lights SHOULD activate. The Jeep is "asleep" and not drawing any power.

You said that you tried this broomstick test and the brake lights work, even though you let the Jeep sit a few minutes after closing the last door. THIS IS A PROBLEM. Your Jeep HAS to go into a sleep state or it will continue to draw power. I would recommend you to try the broom-stick test again. To be safe, wait 10 minutes after the last door is closed before pressing the brake pedal.

I am biased, but I am not a fan at all of the outdated and old-fashioned, diode-based towed wiring harnesses. I guarantee that all these companies did was to send updated electrical plug configuration specs to their China-based manufacturers and they sent over the same, 20-year old diode-based system design... and crossed their fingers. Not one of them has likely noticed an extra, fault-sense indicator wire in the tail light wiring harness - let alone know what it is for. Duh!

For readers here, the reason is that for the last 20+ years it has been rather easy to detect a bulb-out fault condition with a conventional light bulb. The system simply looks for the resistance across the filament. If this resistance goes to an open circuit condition, then the light is out (filament is broken). This method doesn't work for LED lights. Additional, non-trivial circuitry has been added to detect bulb-out conditions with LED lights. So, when you purchase that 20-year old, diode-based circuitry (albeit with new plugs that fit your Jeep), do you think they are properly isolating the fault-sense circuitry? I'm not saying with any confidence that this is the problem here - but we've heard plenty of strange stories of lights flashing and horns honking when connecting/disconnecting some of these antiquated, diode-based harnesses. In brief, buy the MOPAR harness (they know what they are doing) or buy our harness (complete physical isolation without diodes) and eliminate these possibilities. Sorry, rant over.
I will give teh test a 10-15 minute try to see if it truly goes to sleep. I am also goiong to hook up my dash cam so I can watch the dash, well actually record the dash ans whatever happens while we are underway. I just did a 4 hour tow, no issues with the charge line installed. The tail lights are sealed LED units so no socket. The diode is SUPPOSED to keep the power from running into the Jeep from the RV. The question is WHY? I towed a number of trips in 2019 and 2020, no issues, just happened this year.
 

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JimN,

I think you are spot-on in isolating what the problem is. The JL's enter a sleep-state about 3 minutes after the last door is closed. As mentioned previously, you can easily validate this by closing the driver's door and leaving the window down. After ~3 minutes you can stick a broom handle in through the open window and depress the brake pedal - and NO brake lights SHOULD activate. The Jeep is "asleep" and not drawing any power.

You said that you tried this broomstick test and the brake lights work, even though you let the Jeep sit a few minutes after closing the last door. THIS IS A PROBLEM. Your Jeep HAS to go into a sleep state or it will continue to draw power. I would recommend you to try the broom-stick test again. To be safe, wait 10 minutes after the last door is closed before pressing the brake pedal.

I am biased, but I am not a fan at all of the outdated and old-fashioned, diode-based towed wiring harnesses. I guarantee that all these companies did was to send updated electrical plug configuration specs to their China-based manufacturers and they sent over the same, 20-year old diode-based system design... and crossed their fingers. Not one of them has likely noticed an extra, fault-sense indicator wire in the tail light wiring harness - let alone know what it is for. Duh!

For readers here, the reason is that for the last 20+ years it has been rather easy to detect a bulb-out fault condition with a conventional light bulb. The system simply looks for the resistance across the filament. If this resistance goes to an open circuit condition, then the light is out (filament is broken). This method doesn't work for LED lights. Additional, non-trivial circuitry has been added to detect bulb-out conditions with LED lights. So, when you purchase that 20-year old, diode-based circuitry (albeit with new plugs that fit your Jeep), do you think they are properly isolating the fault-sense circuitry? I'm not saying with any confidence that this is the problem here - but we've heard plenty of strange stories of lights flashing and horns honking when connecting/disconnecting some of these antiquated, diode-based harnesses. In brief, buy the MOPAR harness (they know what they are doing) or buy our harness (complete physical isolation without diodes) and eliminate these possibilities. Sorry, rant over.
@CoolTech where can this delay setting be found / changed?
 

CoolTech

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@CoolTech where can this delay setting be found / changed?
I wish I knew. I think most modern cars are now doing something very much like this. I would suspect that the interval to enter sleep state is shorter if you exit the vehicle and use the key fob to lock the doors - a confirmation that you are "leaving".
 

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I am having the same problem. Just got home today. Dead jeep after 2 days of towing. My braking system is all manual, no electric. I have the Mopar tow harness and they installed it.
I know the push button says OFF when I exit the jeep. I did not have this issue last year. Just started this year. I also have the genesis dual battery system. I can jump the dead battery with the other, but I shouldn't have to. Mine is 2019. My brothers 2020 is doing the same thing. His jeep is bone stock. We have both been flat towing for 30 years, no issues untill now.
 

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I am having the same problem. Just got home today. Dead jeep after 2 days of towing. My braking system is all manual, no electric. I have the Mopar tow harness and they installed it.
I know the push button says OFF when I exit the jeep. I did not have this issue last year. Just started this year. I also have the genesis dual battery system. I can jump the dead battery with the other, but I shouldn't have to. Mine is 2019. My brothers 2020 is doing the same thing. His jeep is bone stock. We have both been flat towing for 30 years, no issues untill now.
I have ordered the RVi charger. Only doing that because I am concerned about boiling a battery. ALso new or maybe connected issue. The Auto Start/Stop and traction lights come on from time to time. Stop, restart, messages gone. Lights out. Might be weeks before they light again. Sad.
 

JimN

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I have ordered the RVi charger. Only doing that because I am concerned about boiling a battery. ALso new or maybe connected issue. The Auto Start/Stop and traction lights come on from time to time. Stop, restart, messages gone. Lights out. Might be weeks before they light again. Sad.
Update. The RVi Toad Charger has arrived and is installed. We shall see. And on a somewhat related note. I HATE METRIC! Had to go out and buy three different small packs of different size bolts and nuts to get it installed. I THOUGHT I bought an American Icon here! If I wanted Metric I'd buy a foreign car! And yes I know much of what is built here is sourced offshore and also things built here are sold offshore, but let the world change to match us! When the SHTF, they will all come running to us!
 

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Not sure I understand. I shut the Jeep OFF, nothing should be on when I tow. The Ignition is in the OFF setting. However, apparently the darned thing 'Wakes Up' every time you hit the brakes! This is a drain and over 6 hundred mile two is apparently enough to kill the battery. Perhaps there are other issues that also cause a 'wake up. Anyway, right now I just ran a Charge line with a DIode, I was looking at the RVi toad Charger, but it requires a very expensive monitor to see what it is doing, FIne I suppose if you are also buying their TPMS as it is the same monitor, but no good if you are already covered in that area. If they made it so it would read to Blue Tooth I'd have done it, but apparently they decided to lock up the signal with encryption.I suppose I'll fine out this week. We have a several hour tow. I think I'll grab my meter and check the voltage when we start out and when we arrive, although with the charge line it should be fine and I don't want to take the batteries down again.
I think the brake light / brake pedal thing is a red herring. I have a 2019 3.6 rubicon automatic with no brake system attached yet. I get the same issue when flat towing. A few hours of towing and it’s dead as a door nail. Like many, I thought that I just left it in acc mode at first. This turned out not to be the case. I can put in a charge system, but like many of you, I am not a big fan of fixing symptoms. I would like to know what the problem is before 5 years down the road I have an entire collection of “symptom fixes”.
Has anyone made any headway on what the actual issue is?
I am wondering if it has something to do with the transmission/transfer case not being in “expected” shut off state? Given the push button start/start stop/uconnect remote modem/pixie dust angel fart levitation systems, there is a lot going on in the background.
 

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I think the brake light / brake pedal thing is a red herring. I have a 2019 3.6 rubicon automatic with no brake system attached yet. I get the same issue when flat towing. A few hours of towing and it’s dead as a door nail. Like many, I thought that I just left it in acc mode at first. This turned out not to be the case. I can put in a charge system, but like many of you, I am not a big fan of fixing symptoms. I would like to know what the problem is before 5 years down the road I have an entire collection of “symptom fixes”.
Has anyone made any headway on what the actual issue is?
I am wondering if it has something to do with the transmission/transfer case not being in “expected” shut off state? Given the push button start/start stop/uconnect remote modem/pixie dust angel fart levitation systems, there is a lot going on in the background.
I too would like to know the WHY! Jeep says no need for a charge line, just hook up and go. AirForce One does not draw power. So WHY??!?!?!?
 

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CoolTech

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Understandably, many owners are becoming frustrated with this problem. Like others here, my objective is to try to help diagnose and solve this problem. Let's confirm what we know (feel free to correct/comment):

1. For a fact, we know that there is a current draw in the Jeep that is depleting the battery.
2. This current draw is only occurring when being towed (when disconnected, the Jeep does NOT have a battery issue.)

Near the beginning of this thread, I speculated that the current draw was because the Jeep was NOT entering sleep state. For a fact, if the Jeep does not enter a sleep state, it will draw current and eventually kill the battery.

My ask is that people who are experiencing this problem first help us to know if the Jeep is not properly going to sleep. In short, when you are connected to the motorhome and towing - please leave the driver's window down. Stop in a safe place, leave the MH running and reach in through the open driver's window and press down on the Jeep's brake pedal. (Use a broomstick handle or similar.) If the Jeep's brake lights come on, it is NOT in sleep-state.

If the Jeep is not entering sleep state and/or is waking up inappropriately from sleep-state, then THIS is the problem (current draw) and the next steps would be to try to diagnose what causes it to leave or not enter sleep-state.

If the Jeep IS asleep (as it should be), then the current draw is coming from something else - and the next diagnostic steps will be different.

Again, for those with the problem, satisfy yourself that when disconnected from the MH, you know how to test and confirm this sleep-state. Once you are convinced, it would be great to have you conduct the test the next time you tow.

My theory from the beginning is that something in the tow harness/aux brake control wiring is preventing the Jeep from going to sleep. Let's prove (or not) this theory.... and then the next steps would be to determine what part of the wiring is causing this.
 

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Does the location of the key fob affect any of this. Will the Jeep go to sleep mode if the fob is left inside? Will having the fob in your pocket affect the broomstick test?
 

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Does the location of the key fob affect any of this. Will the Jeep go to sleep mode if the fob is left inside? Will having the fob in your pocket affect the broomstick test?
Those are good questions. We need to get some definitive answers.

My ASSumption is that the Jeep will still sleep - even if the FOB is inside. Think about the scenario when somebody parks in their enclosed garage and habitually leaves the FOB inside the car. If the Jeep didn't sleep, I would guess that the battery would die after a couple of days - so I *think* it does.

If readers here agree.... the first thing to try to determine is IF it is this lack of sleep mode the cause of the battery drain. IF so, then we can start trying to figure out what is causing it to wake or not sleep. However, if we determine that the Jeeps ARE in fact asleep when they should be, then we have to determine the cause of the battery drain. My somewhat educated guess is that it is most likely that these Jeeps aren't sleeping when they should be.

I also use the additional Roadmaster wiring kit that illuminates a red light RMI on my dash when I press the brake on the motorhome to indicate that the Jeep brakes are also being applied.
Onthego - how the heck was that wired up? Let me explain. What you are trying to confirm is that the Jeep is moving its brake pedal. In older cars, this was easy as you would just tap into the brake switch. When the brake pedal arm moves and presses the brake light switch, shazam, you get an indication. HOWEVER, in a JL the brake switch is DEAD when the Jeep is asleep - so it is impossible to get the signal you want from the existing brake pedal switch. So, here's the $1M question. Did the installer put in an additional brake light switch and wire one leg directly to (constant) power? (This would be the RIGHT way to do it... but much more difficult) Or, did they jury-rig something so that the existing brake light switch would work.... which could be part of your problem?
 

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I think the brake light / brake pedal thing is a red herring. I have a 2019 3.6 rubicon automatic with no brake system attached yet. I get the same issue when flat towing. A few hours of towing and it’s dead as a door nail. Like many, I thought that I just left it in acc mode at first. This turned out not to be the case. I can put in a charge system, but like many of you, I am not a big fan of fixing symptoms. I would like to know what the problem is before 5 years down the road I have an entire collection of “symptom fixes”.
Has anyone made any headway on what the actual issue is?
I am wondering if it has something to do with the transmission/transfer case not being in “expected” shut off state? Given the push button start/start stop/uconnect remote modem/pixie dust angel fart levitation systems, there is a lot going on in the background.

I didn’t have the tools or time to chase this/these bug/s. Instead I purchased some high grade SS wing nuts and lock washers. I am able to disconnect the batteries very quickly. I disconnect the system according to the owners manual instructions for vehicle storage.

The jeep does lose it’s Uconnect settings, however after a time it fetches them from the cloud and everything gets back to where is was.
 

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The jeep does lose it’s Uconnect settings, however after a time it fetches them from the cloud and everything gets back to where is was.
A man's gotta do what a man's gotta do. Very clever work around but a bummer you had to resort to this. You are also resetting the ECU (and emissions monitors) each time the battery is disconnected. This may not be that troublesome overall but make sure you have the battery connected ~100 miles or more before you go in to an ECU-based smog test (if your state has that).
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