Battery Warning light on. - Toyota Nation Forum : Toyota Car and Truck Forums

weez · 09-05-2008, 06:12 PM

Car is a 2005 Toyota Camry LE 2.4liter 4Cyl. 62,000 mile. No mod or after market parts.

Issue started after car was sitting for a week, while I was out of town. Came home and turned on car to go to work, and noticed the Battery warning light was on.

Drove car to work about an hour away. Made a three stops along the way and had no issue starting the car, or any noticeable dimming of lights or loss of electrical systems.

Found the passenger side headlight was out and replaced it.(not sure if this is anyway related, but will mention it).

Drove car another hour home from work, no issue starting car, no noticeable dimming of lights or loss of electrical systems.

Found and cleaned Corrosion on the Positive battery terminal.

Checked the battery afterwards, and it was giving 13Volts while car was off. Turned on car with AC going full blast, radio, wipers, and car was at 14Volts. When I turned on the headlights it was at 13Volts again.

Took car to the dealership(25mins away) to diagnose the problem and was told it was the alternator.

Drove car another 25mins home.

Took alternator to auto parts store, they were unable to test the old alternator as they did not have the right connector.

Bought new alternator and installed.

Warning light is still on.

Other than the warning light the car is driving fine.

Any suggestion/ideas?

Thanks in advance.

***new echo owner*** · 09-05-2008, 06:39 PM

Have you check your fuses?

N.E.O.

JSM1284 · 09-05-2008, 06:44 PM

The sensing wire for the battery light may be broken. I had a similar issue, went through 3 alternators before I realized the wires for the alternator were broken inside the wire insulation

workerant · 09-05-2008, 09:19 PM

A normal volt meter will do just as good. If a car park for awhile, voltage should be above 12V. Once the car running and alternator kick in, voltage should be around 13V I think... and if you press on the gas, voltage go up even higher if the alternator is working.

since you are running fine without the battery die, I say something else is wrong.. like jsm1284 said, could just be sensor problem.

gdanaher · 09-06-2008, 04:59 PM

This problem troubles me because I haven't figured out why the light stays on. Does the intensity of the light change between the engine being off and the engine running? Unless things have changed, the principle is this: The wire runs through the positive side of the battery via the ignition switch to the alternator. An alternator just doesn't create electricity like a generator. It sorta needs to be primed like a water pump if you think of that way. That wire provides that little bit of 12 volts to do the job and it flows from the battery to the alternator and in so doing, the light glows. When the alternator stats charging, it balances the voltage and the light goes out. A diode in the alternator prevents voltage from flowing backwards to the battery, thus preventing high amperage from flowing through a small wire. I have seen a dim glow after starting and this was the fault of a failed diode. For the light to stay on with multiple alternators means that obviously something else has failed, but what? All I can think of here is that the wire is touching ground somewhere between the bulb on the dash and the alternator, so look for that. The wire must still be connected to the alternator for it to work. Look for a frayed insulation on that wire toughing ground. If nothing else, jiggle the wire around and see if the light goes out. Good luck, and report back, because this one bugs me.

One more thing. If you have access to another vehicle do this--turn the key on so that the alternator idiot light comes on. Under the hood, pull or other wise disconnect the small wire going into the alternator. Letting it hang lose in space, check back for the idiot light. It should now be out. Do the same to your Camry. If the light is still on, then the wire is grounded and you just need to figure out where. Any chance some rats came to visit the car while it was parked? They like to play games like this. Look for damage to the wiring harness holding this wire.

njerald · 09-06-2008, 05:36 PM

Yes, s/b a direct wiire from the "L" alternator terminal through a resistor, a diode and to the meter.

weez · 09-11-2008, 03:13 PM

OK, replaced the original alternator after it tested good at another store.

Have not checked the fuses yet but will try that tomorrow.

Unhooked the multiple wire connector at the alternator and the light went out.

Where is the sensor located for this?

***new echo owner*** · 09-11-2008, 03:23 PM

I believe it is just a voltage signal from the alternator; the regulator sends a voltage out to the IP to turn of the light.

N.E.O.

njerald · 09-11-2008, 04:53 PM

Quote:

Originally Posted by weez

OK, replaced the original alternator after it tested good at another store.

Have not checked the fuses yet but will try that tomorrow.

Unhooked the multiple wire connector at the alternator and the light went out.

Where is the sensor located for this?

Like, read post #6...............or check the wiring diagram in your Factory Service Manual.