02 SAT VUE - Battery light on

[AWDsaturn]

Hey folks,
Here is the deal. Checked voltage at Batt with engine not running and running...both read 11.89 plus or minus volts.
With engine running and slight tap of accelerator, Batt light momentarily extinguishes and then reappears with engine at idle or high rpm.
Whats up with this ?? Bad Alternator ? The Batt is pretty new..less than 9 months old.
Is the replacement of the ALT a big job ?? Everything looks buried under the hood......geezzz... I hate working on cars.
Any help whatsoever appreciated.
Thanks,
AWDSaturn

[IMkenNY]

Everything points to the alternator, what engine?

[AWDsaturn]

Hi,
Its the 6 cylinder version...How big of a "pain" is the alternator to change ? special tools ?
Thanks,
AWDSaturn

[BobbyP]

Hey folks,
Here is the deal. Checked voltage at Batt with engine not running and running...both read 11.89 plus or minus volts.
With engine running and slight tap of accelerator, Batt light momentarily extinguishes and then reappears with engine at idle or high rpm.
Whats up with this ?? Bad Alternator ? The Batt is pretty new..less than 9 months old.
Is the replacement of the ALT a big job ?? Everything looks buried under the hood......geezzz... I hate working on cars.
Any help whatsoever appreciated.
Thanks,
AWDSaturn

IMO the brushes in your alternator are worn out. They cost anywhere from $9 to $20. When you get the alternator off the engine they're not hard to change. I'm sure there's directions on the net with pics.

Here's an example for an Acura...
http://www.acura-legend.com/vbulletin/showthread.php?t=67026

Back when money was tight, I repaired all my alternators.

[Chazberry]

Hi,
How big of a "pain" is the alternator to change ? special tools ?


It's the usual PITA - no special tools. You pull it out from below. (I initially thought it would never squeeze by the various obstructions, but you can get it in just the right orientation to just barely sneak out of there.) How many miles did you get out of the factory Alt.? Btw - has the belt been replaced lately?

[AWDsaturn]

Hey Chaz !!
Well, I attacked the "ALT" this morning....GEEEEEZZZ...what a "PITA"....What a crummy location...on the bottom of the engine where all the oil and water can get to it. Your right...trying to angle that thing out was not fun. I removed the plastic trim around the bottom of the wheel well to give me more room for removal.
I purchased another "ALT" (remanufactured) from PEP BOYS....$285 bucks...I'll get $50 of it back for the core charge. At present, I am awaiting for the "ALT" to show up from a cross town store. Seems like no one esle had them readily in stock.
The Vue has 82000 miles, I believe the serpentine belt was replaced at 45000 miles..I can't remember for sure.
My wife also told me that the "SES" light was on as well.....dang..what next ...
Stay tuned,
AWDSaturn

[Chazberry]

At present, I am awaiting for the "ALT" to show up from a cross town store. Seems like no one esle had them readily in stock.

Mine went at about 78k I think. I also couldn't find one in stock - had to wait several days for AutoZone to get one. As my battery voltage started dropping after it failed, my speedo quit and I think every idiot light on the dash came on by the time I limped home. Battery was so dead it wouldn't even unlock the doors - luckily the power window came down a little. And my Batt light never went out after changing the Alt AND Batt. I'm anxious to see if you have that problem.

[AWDsaturn]

Well,
The new alternator is in.....geezz.....I tried installing the belt over the "ALT" pulley and it wouldn't go. I checked the routing on the belt and everything looked A-ok.
I even had "full throw" on the tensioner to allow for "max" slack".
Seems like its always something else.
Anyhow, as soon as I get it on...And the BATT full charged, I'll update you on the dash lights..ok
AWDSaturn

[Chazberry]

Anyhow, as soon as I get it on...And the BATT full charged, I'll update you on the dash lights.

Btw - After replacing my Alt. I had to drive 5-10 miles before my SES lgt went out on its own.

[AWDsaturn]

Hey guy,
Finally got the serpentine belt on. I had to call a friend for a extra set of hands. Putting the belt on was a real "bear".
Anyhow, I placed the charged battery in the vehicle and started the car and ran it for awhile. The battery light was gone as well as the service engine light. So far so good..at least for now.
I appreciate your help and everyone else. Thanks folks !!!
AWDSaturn

[Chazberry]

Sweet success!
How many volts are you getting at your battery terminals now?

[AWDsaturn]

14.1 (+ or -) volts !!!! Hopefully, I won't have to work on that thing awhile..but if I do...I know where to come to ;>)

[Chazberry]

14.1 (+ or -) volts

Now I'm wondering if my light is still on because I'm over-charging.
Until I solve this problem I added this gauge to at least tell me my alternator is still working.

[fdryer]

Btw - After replacing my Alt. I had to drive 5-10 miles before my SES lgt went out on its own.

Often when a battery is discharged and hasn't been recharged from the bench using an overnite charger for automatic charging, replacing the alternator won't recharge the battery in a short time as most would think. The alternator's built-in regulator is set to no more than 14.5v DC, plenty of voltage to push the current needed to charge a battery at approximately 10 amps or so, not a lot. That's why it took a few miles before the battery light went off, the battery took enough of a charge that the voltages came up for the light to go off. The battery isn't fully charged though and a long trip is needed for this or else the bench charging method is preferred. A discharged/dead battery will read 12v or less and the difference between the battery voltage and the alternator voltage means the greater the current used to charge the battery but it can harm the alternator by overloading it. Most shops would put a battery on charge while replacing an alternator especially if they know the battery is nearly dead. They don't want to have to replace the replacement alternator if it burns out from putting out its maximum current charging a dead battery and still supplying the electrical demands of the car. Another unknown fact is the fusible link restricts the amount of current supplying the electrical system and charging the battery at the same time to 30amps. Look at the rating for the fusible link between the alternator and the battery, via the starter terminal.

[BobbyP]

I purchased another "ALT" (remanufactured) from PEP BOYS....$285 bucks...I'll get $50 of it back for the core charge.


Wow... Usually for less than $10 you can change the brushes and repair the alternator... You just need to get brave enough to remove ~4 more bolts and replace the brushes.

IMO this wouldn't help most 1st gen s-series owners, since their alternators were being cooked alive on the back of the engine from being poorly located.

[Chazberry]

fdryer - thanks for this info. I did actually recharge my battery before installing the new alternator. While the "SES" light soon went off, the Battery light never did. A few weeks later I installed a new battery - light still on. It's been on for about 9 months now. After first starting the car the alternator is putting out about 14.3 volts and after a little while it drops down to about 14.0. Seems pretty normal. Any other ideas about the light?

[Chazberry]

IMO this wouldn't help most 1st gen s-series owners, since their alternators were being cooked alive on the back of the engine from being poorly located.

Probably the same story with the 3.0 L VUEs. But I was looking at where they hung the alternators on the Honda engines. I hope to hell I never have to replace that bad boy!

[fdryer]

fdryer - thanks for this info. I did actually recharge my battery before installing the new alternator. While the "SES" light soon went off, the Battery light never did. A few weeks later I installed a new battery - light still on. It's been on for about 9 months now. After first starting the car the alternator is putting out about 14.3 volts and after a little while it drops down to about 14.0. Seems pretty normal. Any other ideas about the light?

Normally an output above a certain voltage (can't find the exact number) turns off the indicator. In our case, the signal that's needed goes from the ECM/PCM to the BCM, that either lights the indicator or leaves it off. Wiring somewhere may be the problem. During a start-up all the lamps in the dash are supposed to turn on as part of a systems test then turn off those that aren't part of the start-up that warns of; a battery/charging system, oil pressure, security (Passlock), and maybe one other indicator. The main battery indicator stays on because the engine isn't spinning the alternator until the engine runs, then if enough output voltage is coming from the alternator, the battery light goes off. From your voltage measurements the light should be off but where are the measurements made? If right at the battery terminal there may be a possible voltage drop somewhere that's keeping the voltage at 14.0v when the majority of readings with the engine above idling speed is 14.5v. Your battery is obviously charging but may be charging at a slower rate than optimum. Not enough to cause any concern but it may be the reason the battery light isn't going off. You may have to check all the connections from the battery cables to the fusible link and the two wires leaving the alternator, possibly the grey wire from the alternator. Not sure of color coding though. If there's a single wire from the alternator (L) check to be sure its not corroded in the connector by disconnecting and connecting several times to exercise the terminal connections, a manual self-cleaning of contacts. The large gauge wire is the hot wire coming from the starter terminal and becomes the charging wire as soon as the alternator spins up to speed in idle. This is the fusible link that opens if too much current is output from the alternator.