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My TJ won't turn over but the battery is still good

SeismicWhales

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Joined
Mar 12, 2019
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25
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Salt Lake City, Utah.
I tried to start my TJ last night so I could pull it out of the garage to put my motorcycle behind it and it wouldn't start. I pulled the battery out and took it to Autozone and they said it's still good. My positive terminal connector is a little corroded (I'm going to clean it) and the bolt/nut that goes on it are rusted to hell Does anyone know what size the bolt/nut for the positive terminal is or would just anything that fits work?


What else could I check? The lights will come on and the fuel/oil/etc gauges will move but I hear nothing from the engine. I kinda have a suspicion that something is wrong with my clutch but when I drove it to work a few days ago it was starting and shifting just fine. Could it be the starter or alternator?
 

4.0TJ

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Dec 27, 2018
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US
If it makes a clicking noise but nothing happens, it is likely a bad starter. It also could be a failing clutch interlock. To test this, move a non important 20A fuse such as the rear wiper fuse to the bottom left slot labeled auto trans on the fuse panel behind the glove box. If it starts, then the clutch interlock is bad.

Sent from my SM-G950U using Tapatalk
 
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Steel City 06

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If you suspect the clutch or clutch interlock switch, try starting it with the clutch depressed and the transmission and/or transfer case in neutral. If it still doesn't start, put a fuse in the clutch interlock bypass slot and give it a crank in neutral.

Most of my starting problems end up being corroded terminals or connections. Take every ring terminal connected to the battery posts and clean it with steel wool or Emery cloth. Make all connections, including all ring terminals, battery posts, and battery terminal connectors shiny. Then give it another shot.
 

Jerry Bransford

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A bad battery connection can be good enough for the gauges to work and lights to come on but not be good enough for the starter to work. It takes heavy current for the starter to work which means both battery connections must be clean and tight. It doesn't take nearly as much current for the instruments/ lights to work so a bad battery connection will commonly work well enough for them.

I regularly use a wire battery brush to clean my battery's posts and connectors. Even if a connection looks perfectly fine to the eye it may not be good enough to start the Jeep or even keep it running after a jump start.
 
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SeismicWhales

SeismicWhales

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Joined
Mar 12, 2019
Messages
25
Location
Salt Lake City, Utah.
If it makes a clicking noise but nothing happens, it is likely a bad starter. It also could be a failing clutch interlock. To test this, move a non important 20A fuse such as the rear wiper fuse to the bottom left slot labeled auto trans on the fuse panel behind the glove box. If it starts, then the clutch interlock is bad.

Sent from my SM-G950U using Tapatalk

There's not a clicking noise at all. I'm going to clean the battery terminals and then I'll toss the battery back in and try this.
 
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SeismicWhales

SeismicWhales

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Joined
Mar 12, 2019
Messages
25
Location
Salt Lake City, Utah.
A bad battery connection can be good enough for the gauges to work and lights to come on but not be good enough for the starter to work. It takes heavy current for the starter to work which means both battery connections must be clean and tight. It doesn't take nearly as much current for the instruments/ lights to work so a bad battery connection will commonly work well enough for them.

I regularly use a wire battery brush to clean my battery's posts and connectors. Even if a connection looks perfectly fine to the eye it may not be good enough to start the Jeep or even keep it running after a jump start.
Do you only use a wire brush or do you use one of those corrosion remover sprays?
 

Steel City 06

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There's not a clicking noise at all. I'm going to clean the battery terminals and then I'll toss the battery back in and try this.
If there's no click, perhaps the starter relay circuit is bad. Pop open the relay center and swap the relay with another non-critical one that looks the same and give it another shot.
When you turn the key, a small electrical circuit is completed in the ignition switch. This trips the relay in the relay box, which sends a much larger current to the starter contactor. This contactor is just a giant mechanical relay that can handle hundreds of amps. When it is engaged you'll typically hear a click from the starter. You'll hear this loudest from underneath the vehicle typically. It only clicks once when the ignition switch is turned.

If there is no click, you can try using a short piece wire to jump the starter hot wire to the switched power terminal at the starter and see if it turns. Just be careful and do not attempt it if you're not comfortable with electricity. If it starts, it's not the starter or the contactor, and is likely an electrical failure elsewhere.

Also be sure to check the starter relay fuse
 

Jerry Bransford

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Do you only use a wire brush or do you use one of those corrosion remover sprays?
Wire brush. For corrosion and dirt/grime nothing beats a good mechanical cleaning. Sprays are not going to be nearly as effective. Like trying to clean the kitchen floor by just spraying a cleaner on it. A cleaner can help but it should not be the sole cleaning operation done to the connection.
 
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SeismicWhales

SeismicWhales

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Salt Lake City, Utah.
I used some corrosion remover spray on my terminals and it cleared off some but a lot of the terminal is rusted so I might get a new one. The battery is definitely working though. My lights, AC, and gauges all work.

Starting in neutral or in 1st gear didn't change anything.
If it makes a clicking noise but nothing happens, it is likely a bad starter. It also could be a failing clutch interlock. To test this, move a non important 20A fuse such as the rear wiper fuse to the bottom left slot labeled auto trans on the fuse panel behind the glove box. If it starts, then the clutch interlock is bad.

Sent from my SM-G950U using Tapatalk
I guess the clutch interlock is fine. Moving a fuse from the rear wiper to auto trans didn't do anything. Everything was in neutral when I tried it too.
 
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SeismicWhales

SeismicWhales

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Joined
Mar 12, 2019
Messages
25
Location
Salt Lake City, Utah.
If there's no click, perhaps the starter relay circuit is bad. Pop open the relay center and swap the relay with another non-critical one that looks the same and give it another shot.
When you turn the key, a small electrical circuit is completed in the ignition switch. This trips the relay in the relay box, which sends a much larger current to the starter contactor. This contactor is just a giant mechanical relay that can handle hundreds of amps. When it is engaged you'll typically hear a click from the starter. You'll hear this loudest from underneath the vehicle typically. It only clicks once when the ignition switch is turned.

If there is no click, you can try using a short piece wire to jump the starter hot wire to the switched power terminal at the starter and see if it turns. Just be careful and do not attempt it if you're not comfortable with electricity. If it starts, it's not the starter or the contactor, and is likely an electrical failure elsewhere.

Also be sure to check the starter relay fuse
I swapped the starter relay with the horn relay and and then I swapped the starter fuse with the exterior lighting fuse and tried starting it again which didn't work.


Starting at with the clutch depressed is the exact same as just turning the key without pressing the clutch. I'm not too comfortable messing with electrics on a car so i might see if my uncle and my dad will be willing to help me when they get back from their lake trip in a few days.
 

Jerry Bransford

TJ Guru
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Does your ignition switch feel any different at all since this problem started? A broken ignition actuator pin at the rear of the ignition switch can cause this problem.
 
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SeismicWhales

SeismicWhales

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Joined
Mar 12, 2019
Messages
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Location
Salt Lake City, Utah.
Does your ignition switch feel any different at all since this problem started? A broken ignition actuator pin at the rear of the ignition switch can cause this problem.
I saw this Youtube video that said the same thing:

I just got back from harbor freight with some security Torx bits to take it out.


EDIT: I actually found out that some of my roommates from before I dropped out were in town so I went to grab a burger with them, I'm going to check the ignition switch tomorrow.
 
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PA Patriot

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May 14, 2019
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SE Pennsylvania
Darn. Not sure. I know I had a similar issue but ended up replacing the starter myself and it worked. Diagnosis was that all the battery connected pieces were powered fine and no cranking at all. Walking that starter with a hammer and then trying it worked which told me the starter was the issue


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Jerry Bransford

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Darn. Not sure. I know I had a similar issue but ended up replacing the starter myself and it worked. Diagnosis was that all the battery connected pieces were powered fine and no cranking at all. Walking that starter with a hammer and then trying it worked which told me the starter was the issue
He said he just found that his ignition actuator pin was broken which would prevent the starter from working