Hi, my sister has a 2008 Camry LE 4 cylinder. This morning her battery light came on. I checked the battery and the voltage seemed good. When I started the car the volt meter read about 12.5 volts. When I increased the speed of the engine the voltage didn't change. When I turned on the headlights or the A/C the voltage dropped. I checked the #7 (Alt-S) fuse with a meter and it was good. Also, I have the same battery in my 1999 Camry and I put it in my sister's car with the same results. I am guessing that the alternator is bad. Would you agree or is there something else I need to check? Thanks.

 

The voltage at the battery should be 13.9-15.1v at 2000 RPM.

Check 5A ALT-S fuse.

Make sure the electrical plugs is firmly in place at the alt.

Does the radio work?

 

Thanks for your reply. Voltage doesn't change at 200 rpm. Stays at about 12.5 volts.

Checked ALT-S fuse with meter and it was good.

Checked plugs at alt and good.

Radio works.

 

It appears the alt is bad.

Some auto parts such as Autozone will test the alt for free if you bring the unit into the store.

Are mechanically inclined? If so, before you take the alt off the car check the alt brushes. These can wear out. They are replaceable on car, which will save $$. The internet should have post or video on how to do this.

Note the alt may be different for USA or Japan built car. If Japan built, the first letter in the VIN is a "J".

 

I replaced the alternator with a Denso. The battery light is now off. The battery is charging.

I have a couple questions. The battery voltage is about 12.61 volts with the car off. When I start the car the voltage increases to 13.45-13.55 volts at idle. When I increase the rpm to about 2,000 rpm's the voltage increases to about 13.61 volts. If I turn on the headlights and A/C the voltage stays about 13.61 volts. I thought the voltage with the car running should be over 14 volts. Is this something to be concerned with? Is the alternator defective? Thanks.

 

A little low per spec on alt voltage at 2000 RPM but should be OK.

At night, rev engine to 2000 RPM and turn on a host of electrical accessories. Determine if the headlights dim or other problems occur with the added electrical load such as heater blower.

A battery voltage of 12.6V is considered fully charged.

Between drives having a heavy electrical load (headlights, heater, etc). After the engine is turned off for 30 minutes ,check battery voltage. If 12.6-12.7V the alt is doing its job.