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02 Outback LL Bean
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52 Posts
Discussion Starter #1
So after my post yesterday about "thinking" about selling the car, and stating that it has no lights showing on the dash, guess what I have now?

My wife and I went out last night, as I was backing into the driveway the "Brake" light and the "Battery" light came on. I shut the car off, and restarted, and neither were on. So we went in for the night and I forgot all about it.

Coming to work this morning, the "Brake" light and "Battery" light both started to faintly flicker, and then both came on and stayed on. Before I could get off the interstate, my daytime running lights cut out. My headlights still work, but not the daytimes.

I got off the road and looked at the owner's manual, it says the "Battery" light may be a slipped alternator belt, or an alternator not charging. Belts on, I can't test the alternator at work.

So I'm guessing it may be a blown fuse or relay. Does that sound right? Looking at the manual I see an alternator fuse in the engine compartment, but I don't see one for daytime lights.
 

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03 H6 OBW & 06 WRX Sportwagon
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18,122 Posts
quite likely a failing alternator.

How old is the battery? In Tennessee, maybe anything over 3.5- 4 years is suspect?

Of course, there could be bad connections, bad battery cables, etc.

Most AutoZone -type places can do rudimentary testing of the charging system on the car - and test batteries or alternators pulled from the car.

fuses don't generally fail gradually - though a 'spike' in voltage , or a failing DRL module or something isn't out of the question.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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5,947 Posts
It's not that the car heard you, it's that you knew something was gonna go on the car and you just were slow in thinking of selling it. ;)
 

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02 Outback LL Bean
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52 Posts
Discussion Starter #5
Just tested with the voltmeter. With the car off I had 12.56 at the battery. With the car running I had 12.31 at the battery. With the car running and the a/c on setting three I had 12.16. So I guess I need an alternator. Crap.
 

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2008 Ford Escape XLS - 2002 Subaru Outback
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246 Posts
Just think, it's a better selling point!
 

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03 H6 OBW & 06 WRX Sportwagon
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18,122 Posts
someone mentioned there is a rebuilt from Subaru that is affordable and much higher quality than aftermarket.

try a search if no one replies with specific info.
 

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02 Outback LL Bean
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52 Posts
Discussion Starter #8
First crank with new/rebuilt alternator, I got 12.51 at the battery car off and 14.38 with the car running. After letting the car run for 15 mins I get 11.81 car running and 11.62 with a/c on. After running 20 mins and testing at the battery again with the car off, I get 12.40 and its going up.

Now the weird thing, the dash warning lights are still off, and haven't come back on, even though these numbers are lower than when they lights were on.

Is my rebuilt in Mexico alternator bad? Or is it something else?
 

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02 Outback LL Bean
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52 Posts
Discussion Starter #9
Ok guys here's some more info.


I tested the battery again with the car off 12.4. I checked at the power supply going into the alternator and got 12.4. I then started the car. Upon initial start up I had 14.2, but as I left the voltmeter on the positive and negative points of the battery, it began to go down. I took the car for a drive. Here's where things got interesting. After driving for about 15 mins making loops close to my house, I had the a/c on and it started not blowing cold. Shortly after, like less than a minute the ABS light came on. I was less than 5 miles from my house and headed directly home. While coming home, the speedometer and tachometer shut off. And then started getting all wonky, they would come on, flicker a couple times, needles jumping all over, and then shut back off. And kept doing it until I got home. When I got home, without shutting the car off I tested again 8.51 at the battery. I got none of the same lights I had before.



I've called and got another alternator on order and it will hopefully be here tomorrow. Is a bad alternator the correct diagnosis? Anything else I should check?
 

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01 VDC, 05 R Sedan, 06 BAJA EJ257
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15,483 Posts
Before you spend time, although very little, changing the alternator, you may want to check a few things first as you may have the same occurrence after the 2nd alt:

The alt circuit is fed through the ignition relay and fuse #9 (10A) in the underhood fuse block. The control circuit via the PCM. Very doubtful the PCM is at fault.
Belt
Ground cable condition, fitment to the battery - no frays, tight connection at the battery and block.
Battery Pos cable - same as Ground
Check amperage - between the battery post, then connect the ground side of the meter to the alt casing and check again. If you are losing more than 100 amps to the alternator, its a cable issue or loose ground. If the amperage is low in a charged battery to start with, replace the battery. A weak battery is a major reason alternators fail to start with.
Electricity moves from - to +. If your alt is lacking in ground supply from the battery, it won't start up to send amperage back to the battery.
 

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02 Outback LL Bean
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52 Posts
Discussion Starter #11
Cardoc,

I've got your list printed off and will be checking everything tonight.

I also just got back from having the new/used alternator tested, and it passes all the test at Oreilly's. Guy working seemed very knowledgeable, and took me back and showed me the machine and tested it for me. I want to say the numbers were 14.95 or 15.95. I didn't write them down cause I'm a bonehead.
 

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'14 3.6R Outback
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2,345 Posts
Cardoc,

I've got your list printed off and will be checking everything tonight.

I also just got back from having the new/used alternator tested, and it passes all the test at Oreilly's. Guy working seemed very knowledgeable, and took me back and showed me the machine and tested it for me. I want to say the numbers were 14.95 or 15.95. I didn't write them down cause I'm a bonehead.
15.95 would be bad, so lets guess it was 14.95, which would be good.
 

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02 Outback LL Bean
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52 Posts
Discussion Starter #13
So I checked all the grounds, I checked all the fuses I could in the engine compartment and I got the new/used alternator in, again. When tested with car off battery had 12.11. Car on the battery tested at 14.35. Not 5 minutes in to letting it run the numbers started to go down, and then smoke started coming from the alternator. Immeadiate shutdown and test. 11.51 at battery and at alternator. Cranked again, no more smoke, but the numbers kept going down.

Is it possible that the alternator could test right at startup and then overheat and not charge the battery correctly?

I'm planning to take the alternator back and try my hand at another new one. Should I take my battery in and get it tested as well?

And 8 mins. That's how long it took me to get the alternator out this time.
 

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02 Outback LL Bean
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52 Posts
Discussion Starter #15
Battery tested good.

I have a new/rebuilt alternator to try it all again. I just can't figure out why it would test in the right range initially and then drop off so quick.

Are there other known ground locations I should check? I checked all the ones in the motor last night.

Are there fuses in the car itself that might be at fault?

Again I'm really at a loss and getting kind of frustrated at this point.
 

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03 H6 OBW & 06 WRX Sportwagon
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did they test the one you brought back?

did they test the replacement one before you left with it?

maybe this one will be good.
 

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02 Outback LL Bean
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52 Posts
Discussion Starter #17
They tested the new/used one before I left and it tested good.

They just replaced the other one because it had been smoking.

I asked about how their tester worked and he said it does a charge like at startup and then measures if the alternator comes on, and when/if the alternator comes on it measures the output from the alternator.

We'll see.
 

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The drop in Voltage could have been a defective replacement alternator. It has happened before.

But it could also have been caused by a bad battery. How did they test the battery? In many cases, they just load test it. But they don't usually put it on a charger (unless it's discharged) to see what happens when 14+ Volts is applied.

The fact that all looks good initially on the car, but then things go bad, could be because a plate in the battery is shorting after the charging current from the alternator is applied for a while.

As noted, grounds can have significant effects. One way to check them is to start the engine and (assuming there's no smoking) with the engine running at about 1000 rpm and some lights on, measure the Voltage between the battery negative post and the alternator case. It should be only a few hundredths of a Volt (e.g. 0.05 Volts). (Most digital meters will read this low on the lowest Volts range). If it's up a lot higher, there's a bad ground.
 

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03 H6 OBW & 06 WRX Sportwagon
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any feeling for old the battery is?

seriously, even without sulfating from total discharges, they may only last 4 years in Tennessee.


 

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02 Outback LL Bean
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Discussion Starter #20
Lucky-I meant to look at the date and forgot. I will in a few minutes when I head home.

plain OM-I've not measured between the negative post and the alt cover. I will and get back to you.
 
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