I have lurked the forums for quite some time but never created an account. So Hi Everyone. I have a 2001 IS300 with 175k miles.

So my car has been running fine but won't start anymore. I put the key in the ignition turn it and the dash lights/radio light up but when I go to try and crank it nothing happens except a click sound and the dash lights go off like if the battery dies. I can turn on my dash lights but when I turn on the headlights the battery dies. When I have the key in the ignition with the dash lights on and step on the brake pedal the battery dies. I noticed the interior lights are dim but my radio works the air works but it will not start. Also when I unlock/lock the car with the alarm key it makes the beeping sound (sounds weak) but the turn signals do not light up like they usually do. This has happened since the car won't start. I tried jump starting it as well and it would not jump start.

Things I've done:
- Battery tested at two different Advance Auto Parts - both said it’s a good battery
- New Alternator put in August but got it tested anyways - Good Alternator
- Starter tested at two different Advance Auto Parts - both said it's a good Starter
- Checked my battery gound + starter ground both look good and on tight.
- Checked my fuses under the dash both driver + passenger side all good
- Checked the fuses under the hood and all good.
- Battery Voltage shows 13 on my dash before trying to crank it.

Is it a bad relay or anything else? Need help as this is my DD. Thanks.

 

Update. I cleaned my battery Terminals today and the battery no longer dies when cranking or pressing the brake pedal or turning on headlights. But still no crank just a slight click and dash lights dim and buzzing sound. Any ideas?

 

I had that happen on my 2001 Lexus is 300 i would turn the key and it sounded like a click sound but car would not turn on I fix it by buying a brand new battery

 

Check your starter, check your starter relay.
Does your car have a manual transmission? Can you push start the car? What happens when you try to jump start the car?
Honestly, it doesn't sound like an expensive fix. I would take it to a garage and have them check it out.
If you get the car running and idling then you'll know that the problem has to do with the starter. What is the battery voltage when idling?

 

Starter relay is good + had starter tested and it is good. Its Automatic so can't push start it.

Same thing happens when I try to jump it just the click and buzzing sound.Voltage gauge shows above 12v for battery before trying to crank.

Towed it today to a local shop. Hopefully it is something not expensive. Either way I'll keep this updated in case someone has the same issue later on. Thanks anyways.

 

Just got it back and it is running.

It was a bad battery. The battery showed good voltage of 12.5 but when trying to crank it, the battery would not hold the voltage.

 

Sounds about right, except I am surprised that you weren't able to jump start the car. The battery's voltage at rest is irrelevant. As you've discovered the hard way, the voltage will drop when a load is applied. If the battery was dead (minimal remaining energy), it can still show a 12.5 V but not have enough "juice" to turn the car over.
Glad it was a cheap and easy fix.