Alternator/battery problem
- Thread starter cali_92
- Start date
JPNinPA
Active member
The 12A when running could be 3 possibilities.
1.) There is a short in a ignition powered circuit.
2.) Your alternator connections are poor and not allowing the alt to supply the system. Sa all power comes from the battery until drained.
3.) You have enough added components on ign powered circuits your alternator can't supply and the battery is drained.
How many add on components do you have and what is the wattage of each?
What size alternator do you have?
Did you buy the multimeter? ( I take it you didn't withthe free ele check you mentioned)
1.) There is a short in a ignition powered circuit.
2.) Your alternator connections are poor and not allowing the alt to supply the system. Sa all power comes from the battery until drained.
3.) You have enough added components on ign powered circuits your alternator can't supply and the battery is drained.
How many add on components do you have and what is the wattage of each?
What size alternator do you have?
Did you buy the multimeter? ( I take it you didn't withthe free ele check you mentioned)
I don't know if this would help at all but for years I haven't had low beams only brights. I bought and installed news ones but still the same thing no low beams. So put old ones back in. Would lights b a part of the ignition system. Circuit? Didn't buy the multimeter. The only extra componets I have is an amp and sub that I have disconnected right now because it drains the battery to fast. Also just conferemed that i bought the correct alternator with 90A. All the connects look clean and tight to me. I've taken off and cleaned several times. How/where do I check for a short in my ignition component?
superj
Active member
is your light under the hood staying on when you turn your jeep off? are your interior lights staying on when you park the vehicle?
you want an easy way to find which system you short is on? turn off your jeep and lay so you can see the fuse box. pull each fuse out and listen for the pop of electricity. since your jeep is off, you should have no pops on anything except the radio and the lights for the door since you have to door open. you can disconnect your radio to stop that one and unhook the switch on the door you have open to stop that one.
do this in a quiet area because the pop is really faint. this is the most inexpensive way to find which system has a short.
you want an easy way to find which system you short is on? turn off your jeep and lay so you can see the fuse box. pull each fuse out and listen for the pop of electricity. since your jeep is off, you should have no pops on anything except the radio and the lights for the door since you have to door open. you can disconnect your radio to stop that one and unhook the switch on the door you have open to stop that one.
do this in a quiet area because the pop is really faint. this is the most inexpensive way to find which system has a short.
JPNinPA
Active member
That's a good idea but he had a free test and said the current was okay when off. I dont know how low the Okay is but in my book it should be less thean 100mA. Also he said the battery drained when running.
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JPNinPA
Active member
For the CEL I believe you turn the key on and off three times and count the CEL blinks. It should give a 2 digit code. With the code you could google it as the ODB codes are posted in many places.
How are you sure the correct amp is 90A? Is this stock size?
How many watts is the amp?? When did you install teh amp?
EDIT: I Recall you disconnected teh amp.
How are you sure the correct amp is 90A? Is this stock size?
How many watts is the amp?? When did you install teh amp?
EDIT: I Recall you disconnected teh amp.
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JPNinPA
Active member
To track down the short switch the multi meter to current.
Put the leads in the meter where you could measure current. Some multi meters have only two places for the leads, others have three common (black), measure voltage or resistance (red) or current (red).
Disconnect the positive battery terminal
Clip or fasten the red lead on the positive terminal and the black lead to the positive battery cable.
You should see less than 100mA with the car off. (Memory for the radio)
Being you have more current draw when the engine is running you could switch the key to on position.
With the ignition in the on position with the engine off you may see more current as the fuel pump will kick on.
Find the fuse box and start to remove fuses. Start with the radio. Watch the ammeter for changes in current.
This method will tell you what circuit to look for the short.
Once you find the circuit, check all accessories on that circuit until the problem is found.
Here is the meter I use.
PS start on the highest current setting.
Put the leads in the meter where you could measure current. Some multi meters have only two places for the leads, others have three common (black), measure voltage or resistance (red) or current (red).
Disconnect the positive battery terminal
Clip or fasten the red lead on the positive terminal and the black lead to the positive battery cable.
You should see less than 100mA with the car off. (Memory for the radio)
Being you have more current draw when the engine is running you could switch the key to on position.
With the ignition in the on position with the engine off you may see more current as the fuel pump will kick on.
Find the fuse box and start to remove fuses. Start with the radio. Watch the ammeter for changes in current.
This method will tell you what circuit to look for the short.
Once you find the circuit, check all accessories on that circuit until the problem is found.
Here is the meter I use.
PS start on the highest current setting.
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i dont believe i have a light under my hood. and everything(lights) seems to b turning off when i turn the car off. the problem is when i run the engine. im thinking its more and more a light problem that just got worse lately. because i've been drivin it to the stores etc. during the day and not using lights and the radio a little bit because it didnt seem to drainthe battery. but tonight when i was using my lights for a goo distance of a few miles my battery died fairly quick and then my engine dies and i cant start it again. i kno i cant start my eng. with out a battery/jumping it but it should b able to run with just the alt. working. and when i was driving it my eng tried to die out and then i decided to turn my lights out and it didnt try to die out so fast. aactualy i think it might have not died at all. so either my lights r the problem or they just happen to just using the normal amount of juice and killin the battery, i think u guys will understand what im tryin to say.
JPNinPA
Active member
I get what your tring to say but I still have to ask: How are you sure the correct amp is 90A? Is this stock size?
If there are no additional circuits the stock size alternator should charge all you have on while running. If you had that multi meter you could check the charging voltage comming from your alternator. Your battery should be 12.5V and while running 14.5V. Anything higher is an issue.
So you think it's the lights. Are the new lights a higher wattage? What you could do as a test is while running pull the fuse to teh lights and see if thr draining goes away.
I don't know if it was asked but are you sure you belt is tight enough and spinning your alternator the correct speed and not slipping?
If there are no additional circuits the stock size alternator should charge all you have on while running. If you had that multi meter you could check the charging voltage comming from your alternator. Your battery should be 12.5V and while running 14.5V. Anything higher is an issue.
So you think it's the lights. Are the new lights a higher wattage? What you could do as a test is while running pull the fuse to teh lights and see if thr draining goes away.
I don't know if it was asked but are you sure you belt is tight enough and spinning your alternator the correct speed and not slipping?
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SteelHeadz
Super Moderator
If the issue on hitting bumps and everything still dies exist, try a wiggle test. With the engine at idle, multimeter monitoring the battery voltage, wiggle the engine harness starting from the battery area all the way to the ECU and see if you could duplicate the concern. Look for chaffed, pinched or severed wires as well. Check the grounds on the engine block from the battery cable and the grounds from the ECU. With a new alternator, the engine should run with the battery disconnected however, if theres a faulty ground or signal circuit, it will not supply the electrical components any power. FYI, don't run the engine with the battery disconnected for a long time as it will cause damage to the alternator diode. Check the O2 sensor wires as well for a short to the exaust pipes. I've seen this happen once where hitting bumps and everything shuts down when the exaust pipe touched a wire with a burnt insulation from the O2 sensor.
superj
Active member
yup, the wiggle test will find it.
also, if your sure the alt is good, start the jeep and unhook one of the leads from the battery. if it dies, then your alt is not supplying power so you know the wire from the alt to the battery is no good or your alt is no good (still).
its not something to do all the time or for long periods but it is the oldest way to check you alternator. back in the days of generators on vehicles, you could disconnect the battery and the car would be fine but now days, if you run to long with no battery hooked up, some diodes in the alternator burn out, or something. i have forgotten since its been so long but that's the gist of what happens
also, if your sure the alt is good, start the jeep and unhook one of the leads from the battery. if it dies, then your alt is not supplying power so you know the wire from the alt to the battery is no good or your alt is no good (still).
its not something to do all the time or for long periods but it is the oldest way to check you alternator. back in the days of generators on vehicles, you could disconnect the battery and the car would be fine but now days, if you run to long with no battery hooked up, some diodes in the alternator burn out, or something. i have forgotten since its been so long but that's the gist of what happens
i have a new alt in. and tested it b4 i put it in and took it out to test it again it was still good
i dont know what the stock was.. i just got what the guy at carquest said to get after putting my jeep in the computer. then i called back to make sure i got the correct one for my yr/engine size of jeep and matched part #s.
i had it tested its showing that its not charging over 12A. its like 11 or so.
their not new lights that i put in. a few yrs ago my low beams went out on both lights(i've just been driving with brights) and i bought new headlamps hoping i would b lucky and theyd b fixed but it didnt so i just put the old ones back in.
i dont know if the belt is slipping. i dont hear or see any slipping. there are two fixed bolts to mount the alt so i cant adjust the tightness there. i mean i checked the belt, its tight, it looks good to me.
its rainning here so im limited to time i can work on it. usually rain won't stop me from working on my cars but with electrical... i'll wait
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