Electrical Problem: won't start

Jesse164521

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Joined
Jun 10, 2018
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23
Location
Leonardtown Marylnd
Hey guys,

I have a 98 wrangler that has very little done to it because I am a broke college student. A little background before I explain the situation: I am studying Mechanical Engineering and hate electricity. This problem also occurred for one day only about 2 months ago, I let the jeep sit for a day and then it worked just fine.

I drive the jeep and then hear a noise go off, so I look down and see the volt meter through the roof. I decide it is wise to find a good spot to pull over and turn the vehicle off. I take the key out and put it back in the ignition, turn it one click and I have very little electricity(floor lights start blinking, radio won't come on, dashboard lights are very dim and dash volts read 9V). I then proceed to turn it to the starter and everything goes black. No start, no clicking, no electricity. I figured faulty ground, so I check everywhere for spliced cables or broken or back connections, nothing. I take the voltmeter across the battery, and it reads 12.78V. I read voltage across the starter, battery to grounds, lead to grounds and everything reads about 12.70V Until I put the key in the ignition. I place the key in and everything drops to 9V immediately. I turn it one click and voltage everywhere goes to 3.5V. I take the key out and slowly everything returns to 12V after about 30 minutes of waiting. I have a suspicion that it is the ignition switch, but why would floorboard lights flicker if the key is not in and the doors are open? I unhooked all aftermarket lights I have and even tested those, they work fine. The battery reads 100% charged at AUTOZONE. All fuses are good and I pulled a couple relays and they are good.

Like I said, I am broke and love fixing problems myself, but I want opinions from others before I purchase an ignition switch to find out that is not the problem. Suggestions? Suggestions how to check ignition switch?
 
Ive seen some crazy things happen when the terminals and posts are not clean. Pull them both, clean them well with a wire brush so they are shiny, then see what happens.
 
I appreciate your reply,
I did do that. I pulled the terminals and cleaned them off with wire brush. I cleaned the battery and the wire connections. They are nice and shiny now haha. I actually clean the jeep very well typically, like clean everything under the hood as well. So most of my grounds are very clean and shiny already because I just cleaned it 4 days ago.
 
Thank you,

It is not the battery because I have tried jumping it with another vehicle and had this one tested. When autozone tested this battery they looked at me confused because they said this battery is 100% charged and has no problems haha.
 
Jesse, that's what happens if you hate electricity. Sorry but that will make the two of us.
I think it is a faulty ground and will cost you a bit of money to trace it from a dealership technician.
I paid $125 for a dealership just to diagnose an electrical failure for my daughter's TJ.
The more I hated electrical stuff.
 
Make those same voltage tests again where you measured 9 volts but this time, put the meter leads on the center of the battery posts themselves, not on the connectors.

Measure strictly from the battery posts themselves, don't measure from the connector/clamps the cables go to. WIth you holding the meter probes on the posts themselves, have a helper turn the ignition switch to On, then to Start and see what those voltages read from the battery posts.

This test will confirm whether the battery itself is good and whether a bad connection is causing the 9 volt reading you got during one of your tests.

If you get 12.6v to 12.7v at the battery post itself when the ignition switch is in the Start position, move the + lead of the meter to the connector and see what you get with the ignition switch in the Start position.
 
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