"Something" on / from rear beam has snapped. What is it? Picture attached.

Headlight leveling sensor.

 

It’s very worthwhile to disconnect one end of that every few years, flex the ball joints beyond the tiny movement they usually do, redistribute the grease.

if you can get the ball joints lubed and freed up, a funky splint on that broken arm might work as a stop gap fix. Say a tight fitting section of vacuum tube pushed on both sides of the break, and small screw band clamps to keep it tight. Maybe fill the tube with JB Weld too.

 

As ChapmanF said, it's a sensor that measures suspension height so that a computer can properly adjust the headlight up and down aim. The bracket at the bottom and the sensor arm on top both have metal ball studs. The plastic link has ends that snap over the studs. Over time the ball studs rust up and cause the plastic link to seize instead of swiveling when the suspension moves. Eventually it breaks.

Posted via the PriusChat mobile app.

 

Toyota should recommend an occasional inspection of that; it’s a heck of a lot more failure prone, than the driver’s floor mat for example.

 

Looks like headlight leveling sensor link has broken... here's an image of complete sensor with housing and Link circled.

Posted via the PriusChat mobile app.

 

Yeah the ball joints seized at the ends of that link seized, so something had to give.

At least on 3rd gen, probably also on 2nd: you can crawl under without even jacking it up, disconnect the bolts at one end, move those joints through fuller travel, redistribute the grease.

 

Hmm, this thing measures suspension height? Anybody know how it works and what the pin signals are? Folks have been attaching tilt sensors to the alarm system to protect cats. Surely the suspension height must change significantly on the side of a car which is jacked up. It looks like a fairly pricey part, but if it is already on the car, maybe it isn't too hard to power it up when the car is off and read its signal?

 

There's just the one, and it's sort of in the middle of the rear axle beam; it's mostly there to detect angle front-to-back, as you would want for headlight leveling.

I'm sure the reading would still be likely to change with one side of the car being raised, so maybe it would be usable ... it's just not positioned best for that purpose.