1999 lexus lx 470 ABS and brake light is on with a buzz and no pressure

and your question is

Each wheel has a magnetic sensor and a slotted ring that generates the ABS pulse. The sensor can get dirty (rust, mud and brake dust) and have to be cleaned. The replaceable slotted ring often rusts in older cars. The cable from the wheel sensors to the body, while very tough, can get damaged or disconnected. Its usually the front ones.

You may need new rotors.
Subarus requires the same make and size of tires front and rear. Mixing sizes can cause a mismatch in the ABS signals from each end, and this will often cause the ABS light to come on.
The ABS computer may have failed.

If ABS is working more or less correctly, hitting the brakes on loose dirt or snow/ice should result in the pedal kick back and the buzzing of the ABS valve system.

howdie sounds like their could be abs module week or you could have a sensor wire broke on one of the wheels, or the master cly could have a leak does the pedal come bk up right away?ck this out if not get a quote from your local garage its not good to mess around with brakes

sounds like you abs pump is out or going out it will need replaced by a dealer

You found it. and you verified it the solution and the fix is the turn signal switch

The hydraulic system that operates your brakes will not work if any air has gotten into it. Check your resevoir , if it is still full , then I would guess that the brake Master Cylinder is worn out.
The system can be refilled , and the air bled out of all the lines , however , if there is a leak in the system or the master cylinder is bad your problem will not be solved.

if your pedal pulsates when your stopping you have one or more of your brake rotors worped you can get them resurface sometimes but i recommend yust replacing them you can get them auto zone,or advance auto

check brake fluid level.

master cylinder might be of interest, but i would check the fluid level first

i'll suggest this to you as i would anyone that's never experience abs brakes before.... find an empty parking lot and drive forward and make a panic stop. just once so you will know what the brakes will do... the buzzing sound you hear is also felt in the brake pedal ?

check under vehicle on frame rail drivers side, should see abs assembly, disconnect red wire buzzing will stop, will have to replace assembly, will not have abs braking, will have base brakes, if red brake light comes on do not drive vehicle, have towed to repair shop