A couple weeks ago I heard a weird "cranking" type of noise and didn't know what it was. It was very apparent to a knowledgable car person that it was my alternator going bad. It was only pushing out 15(I am not sure what the measurement was I believe it was amps though). So, I went to Auto Zone where they had an alternator for "my car." However, my battery light is still on. Supposedly, the alternator is supposed to put out somewhere in the 120 range and the new one is only putting out 50-60. Is this alright??? Will it hurt my car??? Do I need to get a new battery maybe or is this alternator not sufficient?

Thanks for any help in advance!

 

Having an alternator not push enough current is fine. You might start to get some abs fault codes if you have the air conditioning on, you're rolling down the windows, with the radio on, and your headlights turned on. Basically, if you're running all of your accessories off of your alternator at once, you could have some problems. As for your battery light still being on, one of the common problems with the xtype is that the battery cables get corroded at each end and this can lead to the battery cables essentially acting as smaller cables and letting fewer amps by because of this increased resistance. If you swap out your battery cables or check them for corrosion, and you're still having issues, then I would go talk to autozone and make sure they sold you the correct alternator for your car. Just for turds and giggles, do you still have the part number for the alternator that you bought from autozone? I could do a little check and make sure that it's the right alternator for your car, but to me, if the alternator fits in the car, then it was built for the car, but that's just my thinking.

 

The positive cable is probably bad. I've seen them get so hot they melt the top battery cover. NEVER PUT AUTOZONE JUNK ON YOU CAR, unless it's a Bosch alternator. Any other alternator sucks. Try a new cable and if the light is still on. Taking that crappy alternator off and get a Bosch one, if it's not a Bosch one.

 

ps...and it may be due to the point that was previously mentioned with all my accessories running, but, from time to time, my car has a veryyyyy difficult time turning over to start and it seems to be after I've had all of my accessories running(air con, radio, lights at night) in which case a new battery might not due. Any idea where to get that bosch alternator as a backup plan, I have a feeling a might need it.

@disguay I am going to get the part number here this morning and post it on here so you can check it out. Thanks again for everyones HELP. I absolutely HATE it when my baby is sick....

 

Ok. So it's a Duralast Alternator, part # 13926. Supposedly it puts out 120Amps. However, like I said, I checked it the other day and it is only putting out 55! I'm certain that has to be the problem. Any help would be greatly apprecaited. Thanks Disguay for looking into it further. Please let me know of any recommendations.

 

jmault, think of the alternator output like the output of the water system in your house. When you only use the sink, you will have plenty of pressure (or voltage when talking about the alternator) and the amount of flow will be minimal (or current when talking about an alternator). If you start trying to run your dish washer along with your washing machine along with your sink along with your shower, your pressure at each of these is going to drop because you are pulling a lot of flow. In the case of your car, it is sounding like you having an issue with the alternator being able to supply enough current (or the amount of water you are trying to flow is more than what the pump supplying your house can provide). This results in a significant drop in the voltage/pressure. So, in car terms, your battery is now making up for some of this voltage.

If I was to start trying to isolate down your problem, you are looking at 1 of 2 problems. The less likely thing is you have a bad alternator (the pump when relating to water in your house). The Jaguar alternators are pretty stout and will take a large amount of abuse. The more likely situation is there is a wire that senses the voltage (or pressure when thinking of it in terms of water) and feeds that information back to the alternator. This then causes the alternator to output more voltage and current to restore the system to a preset value. If you have something happen to this wire feeding the information back, the alternator is getting bad information, which will lead to the electrical system running amuck.

By the way, the factory alternator is a 160 amp unit as I recall. While the 120 amp unit will work, you may find that you will be running short on power during adverse weather when you are trying to use your rear defroster, front defroster, seat heaters, wipers, headlights, etc.

If you want some more help figuring this out, let me know. A few measurements with a multimeter and we should have the problem narrowed down to a specific thing.

 

boy I could certainly use all the help I could get. Please advise me on what to do! Thanks so much!

 

Youve already been told what to do and thats replace the pos cable. I say replace both pos and neg plus the link wire from the positive over to the fuse box. Xtypes cable are hugely notorius problem items. They get hiot when old as you drive, resistance goes up, voltage down and you have issues. Replace the cables first. Then see where youre at. You can also go into engineering mode on the instrument pack to monitor the voltage as youre driving.

 

Just out of interest how are you measuring this 55 amps - have you got a DC ampere clamp?
Have you had the battery tested ?

 

jmault, I would first try doing a voltage measurement between the starter and the positive battery post. If you look on the starter, you should see a large post with 2 large black wires attached to it. You will put the red lead of the multimeter there. Put the black lead of the multimeter on the lead center of the positive battery post. If you are getting over 1.000 VDC indicated on the multimeter, your positive battery cable is shot. It is best to do this check with a large load on the car (turn on headlights, A/C on high, and seat heaters). Next, move the red lead over to the lead center of the negative battery post and touch the black lead to a bare metal bolt on top of the engine. If you are getting over 1.000 VDC here, your negative battery cable is bad.

If both of these checks are good (ie, under 1.000 VDC each), then do a quick idiot check and touch the red lead to the positive battery post and the black lead to the negative battery post. It should be reading 13.7 VDC. If you are down around 13.0 VDC or less, then you have a problem with either your alternator or the wiring going to the alternator.

As this point, you will need to be able to access the alternator. So, you may need to remove the wheel well liner. If you look on the alternator, you will see a 3 wire plug on the side of the alternator. You will want to locate the orange/green wire (do not confuse it with the red/green wire). With the engine running, carefully measure the orange/green wire (red lead) to chassis ground (black lead). If you were down around 13.0 VDC or less, you should be seeing that same voltage (or nearly that same voltage) on this wire. If not, then you have a problem with the wiring running between the ECM and the alternator or the ECM is bad. If the voltage is nearly the same (within 1 VDC), then your problem is the alternator.

Hope this helps.

 

Hi Jmault,


Did you manage to get the battery light to go out?
I'm having the same problem!