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My 2017 GC Limited 3.6L has started to do a few strange things lately and I'm hoping someone here can point me in the right direction for a fix.

First - at idle, in gear, while stopped, the voltage will drop down to mid 11's (11.7, 11.6 etc) for a second and then go back up to 14.5 or so for a second, drop down for a second, then go back up for a second, and then it repeats. This continues until the engine rpm is raised above idle. As far as I remember, it's always done this to some extent, but not with the frequency it is now. When new, it would occasionally do this momentarily, but after one cycle it would go back to normal 14.5 or thereabout and stay that way, much the same as when you turn on a power hungry accessory or air conditioning. It's especially annoying at night when I'm at a light and other drivers think I'm dimming / brightening my headlights.

I brought it to the dealer and they thought the alternator was going bad so they ordered a new one and replaced it. While the vehicle was being worked on, the service manager came to me and mentioned they had another customer with a GC and the same problem, where they replaced the alternator and it didn't cure the problem. He said the customer is just living with the problem. I'm concerned that my vehicle is eventually going to break down and get stuck because of it so this isn't a good option for me.

A half hour later when I came to a stop at a light it did the exact same thing. Today it isn't doing it so far (that I noticed) but I'll keep an eye on it.

Second - lately the headlights flicker quickly, similar to when a fluorescent light is going bad and it starts to flicker. It's very hard to notice, but on a dark roadway or when shining on the back of a dark colored vehicle at night it can be seen. I've read some posts on older vehicles where the alternator or rectifier was the cause. This is what I was thinking the cause was, but since the alternator is new, I'd rule it out. Some posts mention a Body Control Module flash, but not for a 2017 WK2. I've gotta hope that the dealer would try a software update before they start replacing parts...maybe I'm being too optimistic! I found one thread where someone recommended an anti-flicker module for aftermarket headlights to cure the issue. I'm willing to try this, but I'd like to see if it can be fixed properly first before I go and put a Band-Aid on the problem.

Third - the remote start failed to attempt to start the vehicle several times without showing any kind of error on the dashboard display (such as hood open, etc). Of course it happened on one of the coldest days this year and then again another day when it was snowing out... It's working today so I can't really continue to troubleshoot it.

I'm hoping someone else has experienced these issues and gone through the troubleshooting process so I can point my dealer in the right direction. I notified them yesterday that the alternator didn't fix the problem and I'm waiting on a callback from them.

Thanks for taking the time to read this and I look forward to some insight from you all.
 

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As a new owner of a used 2016 GC limited I too am experiencing the flickering headlights. I thought I was going nuts when I first noticed but now after researching online I see I am not the only one. Have you found a fix for this issue?
 

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Check all ground connections and the positive heavy cable connections. I had the same issue with a 1996 GC I had. It got progressively worse as the loose connection became corroded due to arcing. It was the positive cable connection.
 

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As a new owner of a used 2016 GC limited I too am experiencing the flickering headlights. I thought I was going nuts when I first noticed but now after researching online I see I am not the only one. Have you found a fix for this issue?
Hello Aaron,
We are certainly sorry to hear about your recent concern. If you were unable to identify a solution from your fellow forum members, we would kindly recommend addressing this with your local Jeep dealer. If you decide to go this route and need further assistance we are available through private message.
Laura
JeepCares
 

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Field Control for the Alternator is done by the PCM, the charging system (as best I can tell by the Description in the FSM) is charging the battery using PWM and measuring the charge state of the battery) it doesn't says how it can it measure the battery on the same circuit its charging the battery, unless its measuring during the null periods of the square wave of the PWM, i.e. I don't know that for a fact but I can't image how else it does it......

If you have Start/Stop, which I "think" started in 2017, then this becomes a very different scenario when the engine is off while stopped and you're running off the battery... ...plus stop/start has a 2nd auxarily battery that complicates the problem cause it could be a one of the two batteries that could be bad....

So you do have a charging system problem, and the flickering lights does sound like it's the result of the PWM (the square wave pulses of voltage going down the line) that is failing to maintain a proper voltage in the system. The pulses of the PWM at the proper power and frequency will be unnoticeable to the system if it is done right, like a fluorescent light's flickering is unnoticeable to the human eye if it is working properly.... ....but like you're experiencing, a flourescent light that is malfunctioning, the flicker is a wrong frequency or voltage and the flickering is very noticeable....

If you have a good Alternator and Battery (bad batteries can drag down the charging system and make it look like the alternator is failing) my first suspicion would be the field control signal from the PCM. And my first suspicion as to what would cause a bad signal for field control has already been mentioned, a bad connection in one of the connectors OR an intermittent short from a chaffed or kinked wire.....

Since it costs nothing and the Dealer probably won't do it, cleaning the connections and making sure they are well seated might fix it.... ...I'd get a can of spray electrical cleaner and battery terminal cleaner/brush....

....find the field wire at the Alternator, following it all the way to the PCM, looking for any damage or signs of shorts.... ...don't start unwrapping it yet, if there is a bad short/chafing/damage you'll see it through the cover or wrapping....

....Disconnect the battery terminals and clean them and the battery posts with the brush... ..Inspect the cables for damage/shorts... ...disconnect the connectors for the PCM, clean both sides, and make sure they are connected and seated fully and properly.. ..inspect the wires for damage or shorts.... ....do the same for the TIPM....

....if that doesn't solve it, you might want to get the battery/batteries checked before going to this point... ....but you might have to unwrap and rewrap the wires to follow the field control wire its entire length to make sure there is no damage to it....
 

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Upon inspection of my batteries 2016 with Start/Stop the positive MAIN battery terminal connection was a little loose. I was able to hand tighten the nut from a half to full turn easily. I haven't had the chance to drive it at night but I am seeing a pretty consistent higher battery voltage readout of 14.7 vs the 14.5 & 14.6 flickering before I tightened the battery cable the day before. I will post back after I drive it at night to see if the flicker went away or not.
 

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Upon inspection of my batteries 2016 with Start/Stop the positive MAIN battery terminal connection was a little loose. I was able to hand tighten the nut from a half to full turn easily. I haven't had the chance to drive it at night but I am seeing a pretty consistent higher battery voltage readout of 14.7 vs the 14.5 & 14.6 flickering before I tightened the battery cable the day before. I will post back after I drive it at night to see if the flicker went away or not.
I'd get the terminal cleaner, clean the terminal and post thoroughly... ...if it was loose, the metal likely oxidized... ...then tighten it with a wrench...

...but loose battery cables are a classic sign of flickering lights and dropping voltages....
 

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My 2017 GC Limited 3.6L has started to do a few strange things lately and I'm hoping someone here can point me in the right direction for a fix.

First - at idle, in gear, while stopped, the voltage will drop down to mid 11's (11.7, 11.6 etc) for a second and then go back up to 14.5 or so for a second, drop down for a second, then go back up for a second, and then it repeats. This continues until the engine rpm is raised above idle. As far as I remember, it's always done this to some extent, but not with the frequency it is now. When new, it would occasionally do this momentarily, but after one cycle it would go back to normal 14.5 or thereabout and stay that way, much the same as when you turn on a power hungry accessory or air conditioning. It's especially annoying at night when I'm at a light and other drivers think I'm dimming / brightening my headlights.

I brought it to the dealer and they thought the alternator was going bad so they ordered a new one and replaced it. While the vehicle was being worked on, the service manager came to me and mentioned they had another customer with a GC and the same problem, where they replaced the alternator and it didn't cure the problem. He said the customer is just living with the problem. I'm concerned that my vehicle is eventually going to break down and get stuck because of it so this isn't a good option for me.

A half hour later when I came to a stop at a light it did the exact same thing. Today it isn't doing it so far (that I noticed) but I'll keep an eye on it.

Second - lately the headlights flicker quickly, similar to when a fluorescent light is going bad and it starts to flicker. It's very hard to notice, but on a dark roadway or when shining on the back of a dark colored vehicle at night it can be seen. I've read some posts on older vehicles where the alternator or rectifier was the cause. This is what I was thinking the cause was, but since the alternator is new, I'd rule it out. Some posts mention a Body Control Module flash, but not for a 2017 WK2. I've gotta hope that the dealer would try a software update before they start replacing parts...maybe I'm being too optimistic! I found one thread where someone recommended an anti-flicker module for aftermarket headlights to cure the issue. I'm willing to try this, but I'd like to see if it can be fixed properly first before I go and put a Band-Aid on the problem.

Third - the remote start failed to attempt to start the vehicle several times without showing any kind of error on the dashboard display (such as hood open, etc). Of course it happened on one of the coldest days this year and then again another day when it was snowing out... It's working today so I can't really continue to troubleshoot it.

I'm hoping someone else has experienced these issues and gone through the troubleshooting process so I can point my dealer in the right direction. I notified them yesterday that the alternator didn't fix the problem and I'm waiting on a callback from them.

Thanks for taking the time to read this and I look forward to some insight from you all.
 

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I had the headlights flickering issue on my 2014 grand Cherokee. After many hours of techs going over everything, it was the battery terminal ground wire attached to the frame that was just loose enough to cause intermittent ground loss and caused the flickering. Follow the negative ground wire to the frame and tighten the bolt.
 

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Thank you I will give that a try because after tightening the positive connection on the battery it still has a flicker. I did buy a new battery terminal cleaner tool and a small wire brush so I will continue to clean the grounds I can get to easily in the cold weather months here on the east coast.
 
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