Battery/Alternator mystery...Help
07-13-09, 07:01 PM
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Battery/Alternator mystery...Help
Please help me figure out what is up with my alternator and/or car.
Here is the story…A month ago my A/C compressor goes out on my GS400. I live in Florida = bad. A couple of weeks before I drop it off at my local A/C mechanic to get fixed It becomes a little harder to start ( I thought because I was not driving it as much and my alarm was wearing the battery down). I let it sit for a whole week before I drop it off, and I have to jump start it to get it over there.
I get my A/C fixed and the guy tells me my alternator is not charging my battery, so he charges it enough to get me home. I order an alternator off ebay and install it that week. The first day after I install it, it seems to be charging the battery because I did not break down. I look at my voltage gauge on my Pioneer and it reads around 13.5V. The next day my wife drives it and tells me that the C/D player is turning off and on and the A/C is losing power. We take it to Autozone for a test and they tell me the battery is dead, so I replace it. They also tell me my alternator is not charging correctly, so I look at my Voltmeter again. This time, the alternator is charging erratically, and does not seem to show any patterns when I turn stuff of f or on or rev the engine. Mind you this whole time my battery symbol on my dash has not gone on. I start thinking it is a bad wire connection on the alternator, so I clean the harness on the back of it and measure the voltage on each of the three wires with the engine running. I measure around 12 volts coming from each wire ( I am not sure what voltage should be there).
I plug it back in and start the car. At first my A/C is off and my alternator starts charging the battery around 13.5-14V (sounds like a supercharger). I notice my battery symbol is lit in the dash while the alternator is running, which I think is odd. This goes on for several minutes, then my alternator gradually slows (maybe even turns off) at around 12V and the battery symbol goes away. Then it starts coming off and on randomly. But when it is charging the battery symbol is lit and when it is off the battery symbol disappears. I turn my car off and on and the alternator starts charging at 13.5V again with the battery symbol lit. This time I turn on my A/C and the voltage quickly drops, I can hear and see the alternator stop charging and the battery symbol goes off.
Right now I have no idea what is going on?? It does not make any sense. Can someone please give me some advice?
Thanks
Here is the story…A month ago my A/C compressor goes out on my GS400. I live in Florida = bad. A couple of weeks before I drop it off at my local A/C mechanic to get fixed It becomes a little harder to start ( I thought because I was not driving it as much and my alarm was wearing the battery down). I let it sit for a whole week before I drop it off, and I have to jump start it to get it over there.
I get my A/C fixed and the guy tells me my alternator is not charging my battery, so he charges it enough to get me home. I order an alternator off ebay and install it that week. The first day after I install it, it seems to be charging the battery because I did not break down. I look at my voltage gauge on my Pioneer and it reads around 13.5V. The next day my wife drives it and tells me that the C/D player is turning off and on and the A/C is losing power. We take it to Autozone for a test and they tell me the battery is dead, so I replace it. They also tell me my alternator is not charging correctly, so I look at my Voltmeter again. This time, the alternator is charging erratically, and does not seem to show any patterns when I turn stuff of f or on or rev the engine. Mind you this whole time my battery symbol on my dash has not gone on. I start thinking it is a bad wire connection on the alternator, so I clean the harness on the back of it and measure the voltage on each of the three wires with the engine running. I measure around 12 volts coming from each wire ( I am not sure what voltage should be there).
I plug it back in and start the car. At first my A/C is off and my alternator starts charging the battery around 13.5-14V (sounds like a supercharger). I notice my battery symbol is lit in the dash while the alternator is running, which I think is odd. This goes on for several minutes, then my alternator gradually slows (maybe even turns off) at around 12V and the battery symbol goes away. Then it starts coming off and on randomly. But when it is charging the battery symbol is lit and when it is off the battery symbol disappears. I turn my car off and on and the alternator starts charging at 13.5V again with the battery symbol lit. This time I turn on my A/C and the voltage quickly drops, I can hear and see the alternator stop charging and the battery symbol goes off.
Right now I have no idea what is going on?? It does not make any sense. Can someone please give me some advice?
Thanks
07-14-09, 12:10 AM
#3
First of all, we do not know the Alternator is the correct one or is a good condition one. If you apply a load such as turning on the A/C the voltage should be between 13.2V - 14V. If it doesn't, the alternator is not doing it's job. That is taking the obvious. Now to start figuring it out, here are the solutions. Make sure your accessories belts are tighten, not too loose, not too tight. Get a "DECENT" Multimeter. (VERY IMPORTANT) Make sure the battery of the DMM is still good. Take the leads and touch one lead to the "Postive Cable" not the positive post. And the other to the "Power side" of the alternator. It should read battery voltage. A Fully Charged battery is 12.6V. Now with this procedure, I am assuming you have a Fully Charged battery. If you see voltage drop, you would need a new cable for the power side if that makes sense. You alternator is rated at 100 AMPs I believe. Get one from DENSO, it's OEM. Don't get aftermaket. Overall, belts should be tightened correctly, get the correct alternator, battery cable is in good condition. Most likely you won't problems with the charging system when it is running. GL and hope that helps.
07-14-09, 08:33 AM
#4
First of all, we do not know the Alternator is the correct one or is a good condition one. If you apply a load such as turning on the A/C the voltage should be between 13.2V - 14V. If it doesn't, the alternator is not doing it's job. That is taking the obvious. Now to start figuring it out, here are the solutions. Make sure your accessories belts are tighten, not too loose, not too tight. Get a "DECENT" Multimeter. (VERY IMPORTANT) Make sure the battery of the DMM is still good. Take the leads and touch one lead to the "Postive Cable" not the positive post. And the other to the "Power side" of the alternator. It should read battery voltage. A Fully Charged battery is 12.6V. Now with this procedure, I am assuming you have a Fully Charged battery. If you see voltage drop, you would need a new cable for the power side if that makes sense. You alternator is rated at 100 AMPs I believe. Get one from DENSO, it's OEM. Don't get aftermaket. Overall, belts should be tightened correctly, get the correct alternator, battery cable is in good condition. Most likely you won't problems with the charging system when it is running. GL and hope that helps.
gl
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