Q: I have a 1996 Lexus Es 300. This morning on the way to work the battery light came on and the radio went off.

asked by on October 19, 2017

I have a 1996 Lexus Es 300. About a month ago I left my lights on and it drained my battery. I received a jump and the car has been running fine until today. This morning on the way to work the battery indicator light came on and the radio went off. After a few minutes the battery light went off and the radio came back on. It kept doing this all of the way to work. When I got to my destination, I turned off the lights, heater and radio and then turned off the car. I waited about two minutes and tried to crank the car and it would not crank. Do you think that this is a problem with the alternator or do you think the problem is with the battery.

My car has 270000 miles.
My car has an automatic transmission.

I would suggest having the alternator checked to determine if it is receiving the proper amount of voltage from something called the voltage regulator. The voltage regulator regulates the charging voltage that the alternator produces, keeping it between 13.5 and 14.5 volts to protect the electrical components throughout the vehicle. The voltage regulator controls the field current applied to the spinning rotor inside the alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 volts, the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 volts, the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated. When the voltage regulator is not working properly, this may cause the alternator to allow the power the alternator supplies to drop resulting in the battery dying again. I would suggest having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Lights went out while driving

If fuses and relays are good, there are other possible causes. The ignition switch may have failed internally. If the circuitry inside the electrical portion of the ignition switch has a break or short, it can cut power to the...

Car starts, but car won't go into gear

If in fact the headlights and the shifting issue were a result of changing the battery, the only circumstance that I can think of would be a voltage spike. Was the ignition key on when you connected the battery? Did...

Car accelerates very slow when it hits 20 mph and neutral shift on dash starts to blink.

Either the transmission has thrust bearings or bushings that are worn causing the internal parts to go out of balance or there is an issue with the fluid is low causing the gears to slip. If the fluid is full...

Related articles

A Buyer’s Guide to the 2012 Lexus LS
With With a four-generation legacy spanning a quarter of a century, the Lexus LS may not be the riskiest, most cutting-edge vehicle in its class but its devotees don’t mind – the reliability, near perfection of design, and pronounced bent...
How to Get Lexus Dealership Certified
Lexus dealerships offer automotive technician jobs to those who are Lexus certified through UTI’s Toyota Professional Automotive Technician program.
A Buyer’s Guide to the 2012 Lexus GX 460
It It may be hard to believe, but luxury and adventure can go hand in hand – especially with the 2012 Lexus GX 460. From its luxurious interior with a variety of features to its high-quality build, off-road prowess and...