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Just to add on. I drove vehicle last night and indeed the low beam headlights were pointed more upwards so I could better see the road ahead. So the annoying blinking AFS light is gone away and the low beam headlights actually light up the road. I’m glad to have this working properly now. The only open question in my mind now is if the headlights are properly aligned and if I skipped a calibration step with the new sensor. If anyone knows if there is a special calibration step when you replace the axle height sensor, please chime in.

I just fixed this problem on my 2004 LS430. The blinking AFS light was due to a faulty ride height sensor on the rear axle. On my LS430 it’s on the driver’s side rear axle just behind brakes. My symptoms were the AFS light would flash all the time independent of the AFS off switch setting. It didn’t even matter if the lights were on, the blinking occurred day or night. When head lights were on they tended to point too low so they didn’t light up enough of the road (on low beam). I suppose this is the way they are designed so if the mechanism fails the lights don’t point too high an blind oncoming drivers. The replacement part was $422 and that’s after I called 4 dealers in my area. One dealer had price at $496 before taxes!! So parts pricing is far from standardized. It pays to shop around. This part has a manufacturing cost no more than $40 so you can see the margins dealers make on parts. The failure mode was the bearing on the sensor arm seized due to water ingress and corrosion. Frankly it’s a poorly designed part and it isn't a surprise to me it eventually failed. Anyway with the bearing seized this caused the actuator arm to force and eventually break the sheet metal mounting bracket for the sensor. This occurs because up and down motion of axe moves the actuator arm and if it can't rotate something else had to give. The sensor is a pretty simple variable resistor (potentiometer). The position determines a resistance divider that sends a voltage signal out proportional to the sensor position. When I opened up the resistor portion of the sensor you could also see the resistive material was worn badly so even if the bearing hadn't seized it was possible the inside was going to become an electrical open and fail soon anyways. Installation was pretty simple. Removed old sensor and mounted the new one via two bolts on the mounting bracket. Then connected the cable harness. The actuator arm (via a linkage) is held in a locked position presumable for shipping purposes so it doesn’t be turned beyond intended travel range. I also wondered if it came locked in a specific position for initial calibration. So I turned on the car before I connected the actuator arm so the computer could read the factory set position. At this point I could see my flashing AFS light went away so I knew I was on the right track. I then put rear wheel back on and lowered car off jack to level position. Now I connected the actuator arm to the axle bracket. I had to shimmy a bit to get at it but it was not to difficult to reach. I first removed the small screw with that held the actuator frozen and discarded the screw and the small holding bracket. I the fastened the actuator arm aligning it to the same marks one the axle bracket where the old sensor connected. Tightened up the locknut and I was done. I took a test ride and no more flashing AFS light. Tonight I’ll see if more of the road is lit up. I don’t know if there are additional steps to calibrate the sensor after an install. Maybe someone reading this can add on if there are additional steps to calibrate. I expect I’ll be doing this repair again in the future (because of poorly designed sensor) but next time it won’t be as much a mystery. I now know why each of the four dealers I called had this part in stock and were quite familiar with what it was. Can you say frequent failure scenario? ;)