I have a 2011 Lexus es350 with around 65,000mi and I was driving it normally with no warnings or anything. All of a sudden everything started to turn off and on (the gauge cluster, climate controls, screen) and the battery light, check engine light and vsc light came on. I was able to pull into a parking lot and as I was pulling in, the power steering went out, after that I turned the car off and it would not restart. I have a radar detector that has a voltmeter built into it(not sure if it is accurate or not) but when I read the voltage with the ignition on it read 6 volts. I took the battery out and got it tested at an auto zone and the battery was so dead it wouldn’t even test. I am getting rid of the car soon so I bought a cheap battery from auto zone and put it in the car. It started and ran fine but the radar detector was only reading around 11.5-12 volts with the engine on which isn’t in the 13.7-14.7. Does this mean my alternator is bad and I should replace that too?

 

The alternator is bad.

 

Yep and if the voltage drops slowly as the car runs it's definitely a bad alternator.

 

Agreed, alt is bad. It should be putting out 13.5+ volts at idle. Closer to 14 at 2K+ rpm. Those are a PITA to replace. You have to remove the the fan and radiator hoses. The radiator can stay but you have to unbolt it to move it some to make way when pulling out the alt.
https://www.clublexus.com/forums/es-...regulator.html

 

For sure the alternator is bad, most likely the brushes.
They can be replaced without removing the alternator and they cost $20-30.

 

This exact same thing happened to me 3 weeks ago. My car was a 2008 ES350 with 98k miles.
I just pulled off a highway. All of a sudden, the radio was crackling, then the VSC, Brake, Batt lights appeared, when I step on the brake, the cluster needles jump up and down, the cluster lights flickered, the engine was losing power, the transmission wasn't shifting right.
I was about 3 miles from my house. Lucky, as soon as I was turning off the main street, I completely loss all power, and I was able to use the momentum to pull on the driveway and pushed really hard on the brake halt the car from hitting the garage door.

I checked the battery voltage, it was showing very low voltage. I hooked up an old school (from the 80s) battery charger to it (the battery still in the car and connected). After about 1 hr, I unplugged the charger, checked if the car had power now, and still no power at all.
I notice both the charger and battery got really hot. So I plugged in my newer charger, I wouldn't turn on, but kept beeping. I looked at the charger manual, it said the beeping was the code for reversed polarity. I know I hooked up the charger correctly. I said ok, the battery was bad.
I disconnected the terminals, test the voltage again, it showed 12v. I reconnected the terminals, measure the voltage again, it showed no voltage. I disconnected the battery terminals, use the volt meter, but set it to continuity test mode, touched the positive and negative terminals with the probes,
I was getting continuity beeps. I said, oh, the alternator must be the culprit. To confirm, I disconnect the lead wire from the alternator (the single larger wire), redo the continuity test, I had no more beeping. I concluded the alternator must have shorted somehow.
With the alternator lead disconnected from the alternator, I put the battery back in, turned on the car, I was getting power. I was able to start the engine, put it in reverse and drive and things seem to be fine at that point, except for the alternator.

I just finally replaced the alternator with a Denso reman from Toyota Dealer of Longo in Prosper TX on this past Saturday. Things seem to be fine now.

 

Is there any video on how to do that?

 

It is a PITA to replace and a shop will charge several hundred $. FYI the Camry is a mechanical twin to the ES. This is one of many similar videos on YouTube.

 

I don't like the videos that show replacing the radiator without removing the cooling fans and at least loosening the radiator so that you can tilt it towards the front of the car (which is how I did it after draining the radiator).

There is a bolt for a bracket on the underneath side of the alternator that you can't get to without making room for a socket wrench. There is a wire attached to this bracket and you'll rip it out if you attempt to remove the alternator using these shortcut videos. They ALWAYS skip over that little tid bit of information.

Here is the video that I used when replacing my ES350's alternator (the phantom bolt appears at the 19:50 mark of the video):

 

Here is a quick way to fix it. It makes sense. Most of the time bushing is bad. I hate to replace genuine alternators with aftermarket ones. So if one can clean or change the bushing the alternator should work without any issues.

The video link is not working it says "Playback on this website is disabled by the owner" but when you go to YouTube and search for this it will be able to pull up the video

ROADSIDE FIX! REVIVE your DEAD or DYING Alternator with this ALMOST FREE trick! | Gears and Tech

 

Is this the "Hit it with a mallet" trick?

 

​​​​​​​Can you please tell me teh total cost of the alternator replacement? Thanks!

 

For me it was about $1k CAD, $400ish for reman Denso alternator + 4 hours of labour.

It might be a good opportunity to change your serpentine belt if it's getting old too.