BATTERY LIGHT

[es35046]

HELLO, SO MY ES350 HAS A BATTERY LIGHT ON AND NEW BATTERY HAS BEEN INSTALLED CHEKED ALL CONNECTIONS FOR TIGHTNESS AND CORROSION ALSO PERFORMED CHARGING SYSTEM CHECK WITH PASSED RESULT CHARGING AT 13.9V ALSO FOUND NO DTC'S NO PROBLEMS FOUND IN STARTING OR CHARGING SYSTEMS AND VEHICLE RUNS FINE AND LIGHT HAS BEEN ON FOR A WHILE  HAS ANYONE RAN INTO THIS ANY HELP WOULD BE APPRECIATED THX 

[RX400h]

Quote

The battery light on your 2013 Lexus ES350 might still be on after replacing the battery due to several reasons:

1. Faulty Alternator: The most common reason for the battery light to illuminate is a faulty alternator. The alternator converts mechanical energy from the engine into electricity that powers all the on-board accessories and charges the battery. If the alternator develops a fault and stops generating electricity, the entire electrical load of the vehicle will shift to the battery¹. You can test the alternator by measuring the voltage at the battery terminals when the engine is running¹.

2. Damaged Wire or Bad Electrical Connection: A damaged wire or bad electrical connection can stop or degrade the flow of current from the alternator, causing the battery light to come on¹.

3. Corrosion on Electrical Connectors or Battery Terminals: Corrosion on the electrical connectors or battery terminals can also cause the battery light to illuminate.

4. Bad Ground Connection: A bad ground connection can cause the battery light to come on¹.

5. Slipping Serpentine Belt: A slipping serpentine belt can cause the battery light to come on¹.

6. System Reset Needed: After replacing the battery, certain systems in the vehicle may need to be reset. For example, each window has to be reset by starting the vehicle and rolling each window down and holding for 1 second.

 

[Dean2]

Alternator may charge fine when the vehicle is running, but may still have a bad diode. Thebad diode will allow the battery to go flat when parked and can also cause the Battery light to be on. To check the Diode, set your multimeter to AC voltage on the lowest available scale. If you measure ANY AC voltage across the positive and negative terminal, the Diode is done. Most Alternators do not have replaceable Diodes so you will need a whole new Alternator.

[es35046]

I performed the check with my dvom set to ac voltage and checked across my positive & negative battery terminals with engine running there was no voltage the reading is ovolts