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Discussion Starter · #1 ·
Hey guys, long time lurker, first time poster. First off, thanks for putting together such a great community. I've learned a lot from these forums.

I have a 2014 JKU with a taillight issue that I cannot figure out. My left and rear brake lights are on anytime the key is on. The third brake light functions properly but the brake light bulbs in the tail lights are on all the time. When I hit the turn signals the light flashes as its supposed to but then they return to bright (brake).

I've had a Cooltech flat tow harness installed for years but the tail light problem just started. I've bypassed that harness and gone back to the factory configuration with the same issue.

Any insight you guys can provide would be greatly appreciated!

Thanks
 

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:welcome: to the Forum..:wavey:
 

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Discussion Starter · #3 ·
Thanks for the welcome!

To add a little more detail, the issue is really upstream of the tail of the left light. The harness that comes from the upper part of the left wheel well and feeds the tail light has this harness:

Mopar Connection Repair Kit

Pins 3 and 5 are hot when the ignition key is on which is why it looks like my brakes are on. The flash when the turn signals are on but then go back to being hot.

TIA!
 

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Traction control light on? Brake pedal switch is bad or needs adjusted.
 

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Discussion Starter · #5 ·
No lights on the dash

Since the third brake light is functioning correctly wouldn’t that indicate that the brake switch isn’t the problem?
 

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Discussion Starter · #6 ·
Well guys, I put a new brake switch in to see if that would solve the problem and no such luck.

I’m out of ideas...
 

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Discussion Starter · #8 ·
Yeah, switch works fine.

The brake lights work as they should when the key is off. As soon as I turn the key on the L and R brake lights illuminate. Third brake light continues to operate normally with the pedal.
 

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Discussion Starter · #9 ·
Well guys, I bought a rebuilt TIPM, hooked everything up (after tying the battery cables together for a few days) and when I turned the key, no brake lights! For a moment there I thought the problem was solved. I then hit the brake pedal, brake lights came on, and they stayed on. So, at this point I have no idea what the problem is.

Something appears to be shorting out the TIPM. My wiring is all stock since I unplugged the flat tow harness and the trailer wiring harness. The only thing still in the system that isn't factory is the stereo system. I do know that when I pull the fuse for the stereo the brake lights go out but I can't figure out what the correlation is between that circuit and the brakes/turn signals.

I'm open to any ideas you all may have.

TIA
 

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Discussion Starter · #12 ·
OEM bulbs in the taillights and I’ve been using the schematics from BBB.

I have also noticed that some of the Dodge ram guys have the same problem but I haven’t found anyone in this post of the solution. I am still stuck.

Thanks for the replies.
 

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OEM bulbs in the taillights and I’ve been using the schematics from BBB.

I have also noticed that some of the Dodge ram guys have the same problem but I haven’t found anyone in this post of the solution. I am still stuck.

Thanks for the replies.
Sounds more like a fault in the turn signal switch. With the ignition switch on, when you unplug the turn signal multi function switch and see if the brake lights go off. If so odds are good a new multifunction switch will fix the issue. This seems to me to be the logical fix just from a quick glance at the wiring schematics.
 

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Discussion Starter · #14 ·
Problem solved!

We found that there was a stray voltage of about 6.3V in the brake circuit when the ignition key was on.* It turns out that it was coming from the factory amp under the steering column.* It appears that somehow the stereo*circuit shorted to the brake circuit in the TIPM.*

The first rebuilt TIPM was installed before we figured out that the amp was an issue and it appears that we fried that one.* Unplugged the amp, installed another rebuilt TIPM and it didn't work.* CEL's, wouldn't communicate with the transmission control module, etc.* Tried a third rebuilt TIPM and the problem is fixed.**

The rebuilt TIPM is supposed to be superior to the OEM TIPM since the mechanical relays have all been*replaced with solid state relays but time will tell.

We're still not sure why or how the factory amp could fry the TIPM and short to the brake circuit but it seems as though the problem is solved.
 

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Problem solved!

We found that there was a stray voltage of about 6.3V in the brake circuit when the ignition key was on.* It turns out that it was coming from the factory amp under the steering column.* It appears that somehow the stereo*circuit shorted to the brake circuit in the TIPM.*

The first rebuilt TIPM was installed before we figured out that the amp was an issue and it appears that we fried that one.* Unplugged the amp, installed another rebuilt TIPM and it didn't work.* CEL's, wouldn't communicate with the transmission control module, etc.* Tried a third rebuilt TIPM and the problem is fixed.**

The rebuilt TIPM is supposed to be superior to the OEM TIPM since the mechanical relays have all been*replaced with solid state relays but time will tell.

We're still not sure why or how the factory amp could fry the TIPM and short to the brake circuit but it seems as though the problem is solved.
Nice diagnostic work, thanks for reporting back. Glad to hear it's fixed!
 
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