2010 JK Sport won't start, won't crank, won't even click

iamfrisbee

iamfrisbee

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San Antonio, TX
My wife's 2010 JK Sport has an issue with a headlight and her battery died. I jumped the Jeep and then started trying to figure out the light issue. Determined it was an issue with a ground. Found the closest ground on the chassis and disconnected it to clean it to see if that was the issue, while the Jeep was still running. There were sparks. 🤦‍♂️ I actually forgot the Jeep was running. I left it running to charge the battery but then got so caught up in what I was doing... The Jeep slowly sputtered to death. And now, when I turn the key, the dash and everything lights up, but that's it. Turning it to start does absolutely nothing. No clicking, no cranking, no nothing. I have checked fuses. I have tried cleaning that ground. I read a few other posts about testing things on the Jeep and I have discovered that there is no power going to the starter relay. I assume that is somehow related but at a complete loss as to what to try next. Anyone have any ideas?

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The battery definitely needs a jump. That is how I got into this mess. I think I need to replace it. But it was running until I disconnected that ground and now it won't even crank even when being jumped with my other car. LIke there is no indication that I turned the key to start except the dashboard lights change accordingly. I don't get cranking at all. I don't get clicking like a bad starter. It is as if that ground disconnected something important and now whatever that was, it still isn't grounded. I thought maybe I blew a fuse but the fuses are all good. And what I keep getting stuck on is that the starter relay isn't getting any power. But I don't actually know if it is supposed to. Just what I read on another thread.
 
I don’t know how to do that but I’ll try and figure that out and let you know how that goes. The thing is, it didn’t have any issues starting until I disconnected that wire and now, after reconnecting it, it doesn’t do anything. So I don’t think it is mechanical. I’m pretty sure it is electrical. But besides the fuse box, I don’t know what else to check.
 
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iamfrisbee said:
The battery definitely needs a jump. That is how I got into this mess. I think I need to replace it. But it was running until I disconnected that ground and now it won't even crank even when being jumped with my other car. LIke there is no indication that I turned the key to start except the dashboard lights change accordingly. I don't get cranking at all. I don't get clicking like a bad starter. It is as if that ground disconnected something important and now whatever that was, it still isn't grounded. I thought maybe I blew a fuse but the fuses are all good. And what I keep getting stuck on is that the starter relay isn't getting any power. But I don't actually know if it is supposed to. Just what I read on another thread.
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If the battery needs to be replaced, do that. That eliminates the possibility that you accidentally finished killing it. You need enough cold cranking amperage. After that you know you have good power. So from there, you start checking continuity. The power for the starter runs from the battery, through a relay to the key and then back to the relay and then to the starter solenoid. There may be a fuse somewhere along there (been a long time since I did this last). Also check what the battery is putting out, and the what is being delivered with the key turned to start (you'll need help or really good eyes). It should be battery voltage at the starter. If all the wiring checks out, that is power to the relay, and power from there to the starter, then the starter itself is probably the problem. That can happen too. Oh - and if you have an automatic transmission, there is a second switch that permits you to send power to that starter only when the transmission is in park or?
 
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Duster said:
If the battery needs to be replaced, do that. That eliminates the possibility that you accidentally finished killing it. You need enough cold cranking amperage. After that you know you have good power. So from there, you start checking continuity. The power for the starter runs from the battery, through a relay to the key and then back to the relay and then to the starter solenoid. There may be a fuse somewhere along there (been a long time since I did this last). Also check what the battery is putting out, and the what is being delivered with the key turned to start (you'll need help or really good eyes). It should be battery voltage at the starter. If all the wiring checks out, that is power to the relay, and power from there to the starter, then the starter itself is probably the problem. That can happen too. Oh - and if you have an automatic transmission, there is a second switch that permits you to send power to that starter only when the transmission is in park or?
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Manual transmission. I replaced the battery but not sure that was even needed. 🤷‍♂️ Relay does get power; just needed someone to hold the key while I was testing 🤦‍♂️ Now I’m trying to get to the starter but the stupid heat shield is in the way and I can’t get the Jeep onto the ramp so I’m having troubling maneuvering.
 
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If you put the T-case into low range it's supposed to bypass the neutral safety switch. If that makes the starter work then it's possibly the neutral safety switch that's bad.
 
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BLACKJKU said:
If you put the T-case into low range it's supposed to bypass the neutral safety switch. If that makes the starter work then it's possibly the neutral safety switch that's bad.
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I didn’t know the switch was deactivated in 4L 😳.
 
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iamfrisbee said:
Manual transmission. I replaced the battery but not sure that was even needed. 🤷‍♂️ Relay does get power; just needed someone to hold the key while I was testing 🤦‍♂️ Now I’m trying to get to the starter but the stupid heat shield is in the way and I can’t get the Jeep onto the ramp so I’m having troubling maneuvering.
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Modern vehicles aren't built to work on. My favorite to work on was a 1960 Ford 1/4 ton, straight six. I could climb over fender, straddle the axle and stand on the ground. It looked like this with no chrome:


No heat shields at all that I remember.

I notice I had forgotten the neutral safety switch, but there lots of knowledge here. The wire from the relay to the starter may also have problem if the insulation has cracked, which is why you ekectrical check output at the starter end too. Replacing the battery couldn't hurt except some $. If it was the original battery, the odds it was getting crotchety are high. Think of it as preventative maintenance and smile.
 
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