2012 JK Starting Issue

Fatbug57

Fatbug57

New Member
Joined
Mar 11, 2024
Messages
11
Location
Louisiana
Okay, let me explain because I am now very confused about this new to me jeep I bought.. .. Jeep is a 2012 JKU with 3.6 with 101,345 miles and started and ran great when I bought it, started doing mods and removing crappie wiring and aftermarket lights from jeep and had a no start issue. I assumed the starter was bad and replaced it with cheap China starter and worked great for about week, then same issue. Bought a lifetime starter and replaced the cheap one, again ran great for about 6 days and same issue. I removed the starter, got a replacement but jeep still would not crank. I got the start diagram and started going through everything, checking relays, fuses, connections, ignition electronics, etc... The new starter is good, tested that and all battery terminals are good and connections everywhere are tight and still no start... the only thing I had done on the last two starters I did not do on this one was to remove both battery terminals when changing, I only recommend the positive side this time.... So I unhooked the battery and let it sit overnight and reconnected it today and now it starts fine again...

Has anyone had an issue like this and if so what is this resetting that the Jeep cranks???? Is has to be a safety or something of that nature that it resets.. Just pulling my hair out trying to get to the bottom if this issue... Thanks in advance for any and all input..
 
Danarch said:
It might be the transmission safety / neutral switch.
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Automatic, and tried it in 4 low and would not start either. It just has a click I can hear inside the jeep but doesn't even engage the starter. Also, jumped the start relay to check the starter and it will not start but starter wors that way. Even with the key in the on position it just turns over but not start, that's why I said it has to be a safety of some type. Unhook both sides of the battery, for an unknown amount of time, and then you can start it with the key again..
 
Fatbug57 said:
Automatic, and tried it in 4 low and would not start either. It just has a click I can hear inside the jeep but doesn't even engage the starter. Also, jumped the start relay to check the starter and it will not start but starter wors that way. Even with the key in the on position it just turns over but not start, that's why I said it has to be a safety of some type. Unhook both sides of the battery, for an unknown amount of time, and then you can start it with the key again..
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Do you have a small red dot in the upper right of the dash cluster?
 
BLACKJKU said:
Do you have a small red dot in the upper right of the dash cluster?
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No, it recognized the key and goes away with the other dash lights. When I press the brake and turn the key, I hear a click in the shifter area and that's it, until the battery is disconnected, positive and negative, for I would say an hour or more and then it may not do it agafor several days, but it is going to happen..
 
BLACKJKU said:
Yes it's inside the trans, I don't know if a trans shop would have a way to test the neutral start switch or not.
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Okay, but if the switch is bad, it is a make or brake switch, correct? So resetting the battery/ECU by removing the power, should not reset that switch, or am I thinking about this wrong.
 
Fatbug57 said:
Okay, but if the switch is bad, it is a make or brake switch, correct? So resetting the battery/ECU by removing the power, should not reset that switch, or am I thinking about this wrong.
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Your right on that I would think, that's why I though about the security system. Are you sure there's no aftermarket one on? My Jeep had one when I bought it, it's not there now.
 
BLACKJKU said:
Your right on that I would think, that's why I though about the security system. Are you sure there's no aftermarket one on? My Jeep had one when I bought it, it's not there now.
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None I have seen and trust me I have pulled this jeep apart taking out crappie wiring the people before did.. Sound system wire, jacked up aftermath lighting, etc.
 
Fatbug57 said:
None I have seen and trust me I have pulled this jeep apart taking out crappie wiring the people before did.. Sound system wire, jacked up aftermath lighting, etc.
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Have you tried putting the trans in neutral?

It might be worth your time to find out what's making the noise under the Dash, a clicking noise should be a relay.
 
Ye
BLACKJKU said:
Have you tried putting the trans in neutral?

It might be worth your time to find out what's making the noise under the Dash, a clicking noise should be a relay.
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S, tried to start it in park, neutral and 4low.. only hear that click. It should have started when I had the key on and jumped the relay but never fired. It's like something has it shut down, not only the starter but the firing of the coils as well.. Once you reset it, all is good for a few day...
 
Fatbug57 said:
Ye

S, tried to start it in park, neutral and 4low.. only hear that click. It should have started when I had the key on and jumped the relay but never fired. It's like something has it shut down, not only the starter but the firing of the coils as well.. Once you reset it, all is good for a few day...
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I don't know if the TIPM would have anything to do with that or not, but that's where the relays are. It's the resetting after disconnection the cables that throws me off.
 
Not sure this is worth anything, but do you have remote start? There is a safety switch under the hood, drivers front side. Odd thing is if that had anything to do with it I don’t see why a reset would get it to start.
 
Danarch said:
Not sure this is worth anything, but do you have remote start? There is a safety switch under the hood, drivers front side. Odd thing is if that had anything to do with it I don’t see why a reset would get it to start.
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No, I don't think it dies. There is not a start on the key fob..
 
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