Check Gauges & Battery Indicator

I’ve got something similar going on with my 97. Randomly, the meter drops to 9. I’ve cleaned the posts and cables, had battery and alternator check out as okay- but it still dimmed all the interior lights last week.

I’m thinking new battery, but thought I’d see if it could be something else.
 
So what happens with mine is my battery gauge will just Hit the red at any time it feels like it. I had a battery in there with jacked up terminals for a while and it was running well, there was so much corrosion... so i called AAA and got a new battery( and when he took the terminals off it was jacked up bad) .. after a week the battery is already dead and i just got new terminals on and everything, the mechanic said the battery was completely dead when it got there but its literally a brand new battery, so it doesnt make sense. I told them to check my alternator because my battery is not staying charged(like its being shorted out ). They said they cant really test the alternator since the cars battery isnt fully charged... apparently they didnt charge the battery for that long which to me really doesnt make sense. Is it possible i need a new alternator??? Cuz the car starts up but i need to jump it or get it charged a bit. But then the battery goes right back to being dead...
 
Canucklehead Cowgirl said:
I’ve got something similar going on with my 97. Randomly, the meter drops to 9. I’ve cleaned the posts and cables, had battery and alternator check out as okay- but it still dimmed all the interior lights last week.

I’m thinking new battery, but thought I’d see if it could be something else.
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Literally same thing for me.
 
well I replaced the battery and the alternator - just in case. It had 104K on it ... figured it wouldn't hurt, and it still did it. Turns out for ME, the guy that had it before me put the wrong computer in it, waiting for the new one to come in, I'll let you know if that does it for me or not. but electrical SUCKS.
 
Grid8282 said:
So what happens with mine is my battery gauge will just Hit the red at any time it feels like it. I had a battery in there with jacked up terminals for a while and it was running well, there was so much corrosion... so i called AAA and got a new battery( and when he took the terminals off it was jacked up bad) .. after a week the battery is already dead and i just got new terminals on and everything, the mechanic said the battery was completely dead when it got there but its literally a brand new battery, so it doesnt make sense. I told them to check my alternator because my battery is not staying charged(like its being shorted out ). They said they cant really test the alternator since the cars battery isnt fully charged... apparently they didnt charge the battery for that long which to me really doesnt make sense. Is it possible i need a new alternator??? Cuz the car starts up but i need to jump it or get it charged a bit. But then the battery goes right back to being dead...
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that's true. Just charge the battery up and take it in to let them test the alternator.
 
Canucklehead Cowgirl said:
that's true. Just charge the battery up and take it in to let them test the alternator.
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What im saying is they couldnt charge my battery and test my alternator when it was there which leads me to believe they just want me to buy and have them put in an alternator. I mean i had the alternator changed 2-3 yrs ago. Im novice when it comes to knowing about this stuff.
 
But i feel like if the alternator was really bad then the car wouldnt start at all, but let me know if the computer fixes ur problem
 
If the battery is dead and the engine is jump started to get it running, the alternator will NOT (!) be able to charge the battery. Most modern alternators like our Jeeps use require a solid 12 volts from the battery to operate and to be able to charge. And with a dead or a mostly dead battery, the engine WILL die within several minutes of the engine being jump started after the jump start battery is removed. The days of most engines being able to continue running with a dead battery after the jump start battery is disconnected are long-gone.
 
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Jerry Bransford said:
If the battery is dead and the engine is jump started to get it running, the alternator will NOT (!) be able to charge the battery. Most modern alternators like our Jeeps use require a solid 12 volts from the battery to operate and to be able to charge. And with a dead or a mostly dead battery, the engine WILL die within several minutes of the engine being jump started after the jump start battery is removed. The days of most engines being able to continue running with a dead battery after the jump start battery is disconnected are long-gone.
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The terminals and connection to the battery have been fixed already. The mechanic told me to drive it for 20 minutes or so after he had to jump start it in his lot, (still not sure why they didnt fully charge the battery)he then told me in the light comes on again then its the alternator. Alls i do know for sure is that the battery will not stay charged , all my lights get dim, then it dies. Idk if they checked it dor code(they certaintly should have).
 
Grid8282 said:
The terminals and connection to the battery have been fixed already. The mechanic told me to drive it for 20 minutes or so after he had to jump start it in his lot, (still not sure why they didnt fully charge the battery)he then told me in the light comes on again then its the alternator. Alls i do know for sure is that the battery will not stay charged , all my lights get dim, then it dies. Idk if they checked it dor code(they certaintly should have).
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The next step in troubleshooting/isolating the problem is to use a benchtop battery charger to charge the battery overnight. Not 30 minutes or a couple hours, overnight. See what the battery charger says about the battery's health the next morning.

Next, if the battery charger says the battery is 100% charged, take the battery to a battery specialty shop and request it be "load tested". A load test, when properly conducted... and not all are... will place a very heavy electrical load on the battery for no less than ten seconds while watching its output voltage. How much and how fast the battery's voltage drops during and after the load test will tell you the battery's true health. Good or bad.

Nothing can really be known until the health of the battery is known. If the battery takes/accepts a 100% charge overnight and the load test confirms it is good, the next step is to troubleshoot the charging system and the cables for the battery and going to the alternator
 
Jerry Bransford said:
The next step in troubleshooting/isolating the problem is to use a benchtop battery charger to charge the battery overnight. Not 30 minutes or a couple hours, overnight. See what the battery charger says about the battery's health the next morning.

Next, if the battery charger says the battery is 100% charged, take the battery to a battery specialty shop and request it be "load tested". A load test, when properly conducted... and not all are... will place a very heavy electrical load on the battery for no less than ten seconds while watching its output voltage. How much and how fast the battery's voltage drops during and after the load test will tell you the battery's true health. Good or bad.

Nothing can really be known until the health of the battery is known. If the battery takes/accepts a 100% charge overnight and the load test confirms it is good, the next step is to troubleshoot the charging system and the cables for the battery and going to the alternator
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Cool i am currently charging it and ill let you know what happens next
 
ok so battery says full.... just tried to turn the jeep on and it wont even start. its catching a spark i hear the click . but engine is not even turning over. the battery is a week or 2 old i dont think it needs to be tested at all.
 
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Grid8282 said:
ok so battery says full.... just tried to turn the jeep on and it wont even start. its catching a spark i hear the click . but engine is not even turning over.
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If you're hearing things click that's either a bad starter motor, bad connection, or the battery is not really as full as the charger is saying it is.

If you have a volt meter or can borrow one, measure the battery voltage while a helper turns the ignition switch to Start and see what the battery voltage is while the key is in the Start position. If the battery voltage drops way down the battery is bad. If the battery voltage remains at or very close to 12.6 volts then you either have a bad connection between the battery and starter/starter solenoid or the starter is bad. I'd next be measuring the voltage at the start motor itself. At the main connection which connects directly to the battery, and the other connection that connects to the starter relay. See what both voltages are while your helper holds the ignition switch in the Start position. What is the voltage on the starter motor's small gauge and the large gauge wire connections while the ignition switch is in the Start position.
 
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so i just had my battery tested and its fine, AAA told me its my starter and my alternator. im just hoping its not like you had said in previous comments on here and winds up being my ecm(voltage regulator.) BACK TO THE SHOP SHE GOES
 
Hello All Jeepsters ! Got a 2000 Wrangler Sport 4.0l manual that has been a gem with 198K miles. But now , getting the infamous " Check Guages " light, AND Voltage drops to nothing, all way to left about 2 minutes after staring . Does this religiously every start. Have a new battery, mechanics and I have new alternantor installed, checked cables, connections, grounds, etc. They all keep saying gotta be the PCM , which is pretty hard to find . Any suggestions ?
 
Jerry Bransford said:
It COULD be a bad voltage regulator or bad battery but I strongly suspect the actual problem is a lot simpler to fix, not to mention free. Remove both battery connectors and wire brush them and the battery posts so they are bright and shiny clean. Auto parts stores sell a wire battery brush for $3-5 that has a male and female wire brush made for this very purpose.

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Then reattach both connectors tightly enough with the clamp nut on the connectors that you can't move the connectors around on the battery posts even with considerable hand pressure. That fixes most problems like this.

This problem is commonly caused by a battery connector that is corroded/loose/dirty enough that the voltage regulator isn't seeing the voltage from the battery so it keeps increasing the voltage from the alternator to the point the voltage indicator eventually pegs on the right side of the gauge.
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Sitting on the side of the road last week searching for why the battery gauge in the TJ just pegged I came across this post. Just wanted to say thank you and let you know you sharing this wisdom made that day a lot easier for me and the TJ has been running great since.
 
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