Battery light
#1
01-06-2015 | 10:57 AM
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Battery light
I have replaced my battery and a new alternator. For some reason my light keeps coming on. Had it tested and it says nothing wrong detected. I have a 2005 Saturn vue 6. What could be causing problem or is it a defect
Last edited by sw2cam; 01-06-2015 at 11:54 AM.
#2
01-06-2015 | 11:55 AM
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Joined: Mar 2006
Posts: 3,278
From: Arizona
Who tested it and how? Do you have a check engine light or any other name people use for it?
Top right you'll see your user name, next to it is a drop down. Click it, open signature. Add your first name, state, and car to said signature.*
Next get your post count up to 10 asap or your account will be shut down for being inactive. Reply to pictures folks have posted, post a picture of your car, anything to keep your account open.
Top right you'll see your user name, next to it is a drop down. Click it, open signature. Add your first name, state, and car to said signature.*
Next get your post count up to 10 asap or your account will be shut down for being inactive. Reply to pictures folks have posted, post a picture of your car, anything to keep your account open.
Last edited by sw2cam; 01-06-2015 at 11:58 AM.
#3
01-06-2015 | 12:10 PM
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Joined: Jul 2005
Posts: 11,029
From: Slightly off center
Are you sure the replacement alternator has at least the same output Amps spec as the original?
Check all connections at the battery and the ground connection from the battery to the frame for tightness and corrosion. This includes cutting the insulation on the positive cable a few inches to ensure battery acid is not corroding the cable.
Check the DC voltage across the battery terminals with the car cold (not running) and with it running. It is possible your alternator is not putting out enough current to keep the battery sufficiently charged while running.
Report the values back here and we'll see what's what.
Do you have any high current drawing accessories in your car like a huge stereo amplifier? What I'm getting at is there may be another large current draw which is taxing the alternator and it can't produce enough current to satisfy both the battery charging and the draw of current to the amp or other device.
Unfortunately I do not know from where the PCM (or maybe BCM) gets the information from regarding charging system voltage. My guess is across the voltage regulator of the alternator----that's my GUESS.
Maybe another member can fill that in. Might just be a bad measurement issue
Check all connections at the battery and the ground connection from the battery to the frame for tightness and corrosion. This includes cutting the insulation on the positive cable a few inches to ensure battery acid is not corroding the cable.
Check the DC voltage across the battery terminals with the car cold (not running) and with it running. It is possible your alternator is not putting out enough current to keep the battery sufficiently charged while running.
Report the values back here and we'll see what's what.
Do you have any high current drawing accessories in your car like a huge stereo amplifier? What I'm getting at is there may be another large current draw which is taxing the alternator and it can't produce enough current to satisfy both the battery charging and the draw of current to the amp or other device.
Unfortunately I do not know from where the PCM (or maybe BCM) gets the information from regarding charging system voltage. My guess is across the voltage regulator of the alternator----that's my GUESS.
Maybe another member can fill that in. Might just be a bad measurement issue
#4
01-06-2015 | 02:03 PM
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The alternator was replaced by me. It is the same out put as the original one. The battery is new replaced them both at the same time. Had the test done crank was normal, 10.91v no load 14.26v, loaded 14.02v. I will check the wires. Have no amp just basic car for my wife bought it new in 2005.
#5
01-06-2015 | 06:56 PM
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Joined: Mar 2006
Posts: 3,278
From: Arizona
So a "load" test was done.....no load test on the battery and charging system is like doing no test at all.
Again, any other lights on? Check engine light or the like?
Again, any other lights on? Check engine light or the like?
Last edited by sw2cam; 01-06-2015 at 06:58 PM.
#6
01-07-2015 | 07:52 AM
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Ok I am taking my car to an electrical mechanic Thursday. I will report back what he finds. The load test was done on the battery it came back fine. I cleaned all the electrical connections last night like ya'll suggested. Will see if the light comes on today. It only comes on for a few min then goes out.
#7
01-07-2015 | 10:43 AM
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Joined: Jul 2005
Posts: 11,029
From: Slightly off center
You should have a complete load test done on the whole charging system.
The voltages while running are acceptable for an alternator under load. The question is whether it is delivering enough current. Since your battery is not going dead, I'd say so.
From this last post you indicated that the light only stays on for a few minutes. I was under the impression from your first post that the light was routinely coming on and staying on.....just how I interpreted it since you said light kept coming on but never indicated when it went off.....neither here nor there. though the likelihood of the different causes may shuffle a bit.
Being that the battery light is on but short lived, there is a decent possibility that your serpentine belt is beginning to intermittently slip due to wear, thus not spinning the alternator pulley at full speed, and thus not allowing full alternator output. In addition to the belt itself, the belt tensioner may be wearing out, contributing to the slippage of the belt.
Are you sure that neg battery cable to chassis ground connection is clean as a whistle?
Another possibility is that there is a marginal connection in the charging system and when the car gets bumped around on the road, the the PCMs voltage reading gets fubar d then comes right back. Light on....Light off.
Could have the bad luck of a bad voltage regulator on the new alternator.....
Might want to look into belt and tensioner before taking it in if it starts every morning and drives fine---and the light does not STAY on.
The voltages while running are acceptable for an alternator under load. The question is whether it is delivering enough current. Since your battery is not going dead, I'd say so.
From this last post you indicated that the light only stays on for a few minutes. I was under the impression from your first post that the light was routinely coming on and staying on.....just how I interpreted it since you said light kept coming on but never indicated when it went off.....neither here nor there. though the likelihood of the different causes may shuffle a bit.
Being that the battery light is on but short lived, there is a decent possibility that your serpentine belt is beginning to intermittently slip due to wear, thus not spinning the alternator pulley at full speed, and thus not allowing full alternator output. In addition to the belt itself, the belt tensioner may be wearing out, contributing to the slippage of the belt.
Are you sure that neg battery cable to chassis ground connection is clean as a whistle?
Another possibility is that there is a marginal connection in the charging system and when the car gets bumped around on the road, the the PCMs voltage reading gets fubar d then comes right back. Light on....Light off.
Could have the bad luck of a bad voltage regulator on the new alternator.....
Might want to look into belt and tensioner before taking it in if it starts every morning and drives fine---and the light does not STAY on.
#8
05-10-2023 | 07:23 PM
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Joined: May 2023
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Ok I am taking my car to an electrical mechanic Thursday. I will report back what he finds. The load test was done on the battery it came back fine. I cleaned all the electrical connections last night like ya'll suggested. Will see if the light comes on today. It only comes on for a few min then goes out.
#9
05-11-2023 | 12:24 AM
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Joined: Jul 2005
Posts: 11,029
From: Slightly off center
We have no idea what the mechanic said. The dude never came back.
Your battery light is coming on likely because the voltage in the charging system is driving below 12.6 volts DC. Not going to argue over who tested what and what the results were. Taking a new look here.
If only occurring after cold startup, possible that battery is draining some charge overnight or shall I say between cold soaks. When you start the vehicle up from a cold soak, the voltage regulation circuitry sees that the charging circuit voltage is below 12.6 volts and turns on the battery light. The light stays on until the charging system voltage gets back to 12.6 volts . battery light goes out.
If what I described is actually happening, my guess would be current is draining backwards through one or several diodes in the alternator output stage. They have not completely failed as after a few minutes of running The alternator, they go back to behaving as expected.
You can try to check this with a multimeter by measuring the battery voltage when you turn the vehicle off and the battery voltage before you start the vehicle in the morning. DC volts.
If you want to truly put a nail in the coffin, ark your vehicle overnight at AutoZone and have them hook up the load tester before you ever start the car. It should capture the beginning battery voltage as well as the beginning charging voltage. The first 5 to 10 minutes of monitoring should display exactly what it's doing in the charging system. I would say alternator on the way out.
It is possible there is an issue with the voltage regulator only simply not properly regulating the charging system voltage. But those are usually inside the alternators these days so the fix is usually the same.
Your battery light is coming on likely because the voltage in the charging system is driving below 12.6 volts DC. Not going to argue over who tested what and what the results were. Taking a new look here.
If only occurring after cold startup, possible that battery is draining some charge overnight or shall I say between cold soaks. When you start the vehicle up from a cold soak, the voltage regulation circuitry sees that the charging circuit voltage is below 12.6 volts and turns on the battery light. The light stays on until the charging system voltage gets back to 12.6 volts . battery light goes out.
If what I described is actually happening, my guess would be current is draining backwards through one or several diodes in the alternator output stage. They have not completely failed as after a few minutes of running The alternator, they go back to behaving as expected.
You can try to check this with a multimeter by measuring the battery voltage when you turn the vehicle off and the battery voltage before you start the vehicle in the morning. DC volts.
If you want to truly put a nail in the coffin, ark your vehicle overnight at AutoZone and have them hook up the load tester before you ever start the car. It should capture the beginning battery voltage as well as the beginning charging voltage. The first 5 to 10 minutes of monitoring should display exactly what it's doing in the charging system. I would say alternator on the way out.
It is possible there is an issue with the voltage regulator only simply not properly regulating the charging system voltage. But those are usually inside the alternators these days so the fix is usually the same.
#10
05-12-2023 | 09:30 PM
Junior Member
Joined: May 2023
Posts: 2
We have no idea what the mechanic said. The dude never came back.
Your battery light is coming on likely because the voltage in the charging system is driving below 12.6 volts DC. Not going to argue over who tested what and what the results were. Taking a new look here.
If only occurring after cold startup, possible that battery is draining some charge overnight or shall I say between cold soaks. When you start the vehicle up from a cold soak, the voltage regulation circuitry sees that the charging circuit voltage is below 12.6 volts and turns on the battery light. The light stays on until the charging system voltage gets back to 12.6 volts . battery light goes out.
If what I described is actually happening, my guess would be current is draining backwards through one or several diodes in the alternator output stage. They have not completely failed as after a few minutes of running The alternator, they go back to behaving as expected.
You can try to check this with a multimeter by measuring the battery voltage when you turn the vehicle off and the battery voltage before you start the vehicle in the morning. DC volts.
If you want to truly put a nail in the coffin, ark your vehicle overnight at AutoZone and have them hook up the load tester before you ever start the car. It should capture the beginning battery voltage as well as the beginning charging voltage. The first 5 to 10 minutes of monitoring should display exactly what it's doing in the charging system. I would say alternator on the way out.
It is possible there is an issue with the voltage regulator only simply not properly regulating the charging system voltage. But those are usually inside the alternators these days so the fix is usually the same.
Your battery light is coming on likely because the voltage in the charging system is driving below 12.6 volts DC. Not going to argue over who tested what and what the results were. Taking a new look here.
If only occurring after cold startup, possible that battery is draining some charge overnight or shall I say between cold soaks. When you start the vehicle up from a cold soak, the voltage regulation circuitry sees that the charging circuit voltage is below 12.6 volts and turns on the battery light. The light stays on until the charging system voltage gets back to 12.6 volts . battery light goes out.
If what I described is actually happening, my guess would be current is draining backwards through one or several diodes in the alternator output stage. They have not completely failed as after a few minutes of running The alternator, they go back to behaving as expected.
You can try to check this with a multimeter by measuring the battery voltage when you turn the vehicle off and the battery voltage before you start the vehicle in the morning. DC volts.
If you want to truly put a nail in the coffin, ark your vehicle overnight at AutoZone and have them hook up the load tester before you ever start the car. It should capture the beginning battery voltage as well as the beginning charging voltage. The first 5 to 10 minutes of monitoring should display exactly what it's doing in the charging system. I would say alternator on the way out.
It is possible there is an issue with the voltage regulator only simply not properly regulating the charging system voltage. But those are usually inside the alternators these days so the fix is usually the same.
Thanks again and please stay tuned.
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