Three Red Seat Indicators and Beeps while driving

If you don't have an owners manual, then see a dealer.

 

Wow, way to treat a new member. Simple question and maybe someone knows and will have a simple answer. I've always been curious myself about the same thing, but it is not important enough to look it up. If I saw an answer here, I would appreciate it.

 

Those are the rear seat belt reminder lights and are activated by the system sensing weight on one or more of the 3 rear seat positions (the triangle and square symbols are indicating the different seat positions). If you have something in the back seat it can trigger them. If they light up right after starting to move the car it is normal. In the 2022 Owners Manual they are addressed on pages 109 and 591.
If they are just lighting up intermittently with out weight in the rear seat it is probably a malfunction. Additionally, they can be disabled (if I remember right).
Hope this helps.

 

And I supplied a straight forward and simple answer.
There was no "mis-treatment" until YOU showed up.

 

Have to ask. Is your 12 volt battery original? A weak battery can cause all sorts of electrical issues.

 

Well, then, we clearly agree to disagree. I stopped short of calling your behavior demeaning. I wonder what you would have said if I went there. Maybe I'll be lucky enough to find out. lol.

 

On my 2017, IIRC, they light up if you merely open the rear doors as well.

 

Maybe it has something to do with one or both of the rear door switches. Switch not opening (or closing) properly. But then the rest of the behavior, partial illumination of other warning icons on the panel and beeping noises, sounds like electrical gremlins from an improperly booted ECU. OP says this happens at some point while driving, so all the ECU's should be booted and functioning by then. I'm familiar with the three seat belt warning icons but I don't know it they illuminate as a group or individually if one or more seats are occupied and the occupants are not belted. All three of them illuminating at the same time doesn't sound like seat sensors amiss. I see them light up every time I make my Prius ready as part of the POST (power on test). I would start with the easy stuff and have the battery load tested and + and - connections checked.

 

And so did YOU.

My teachers often said: "Look it up yourself. You will remember it longer."

Then......asking a question in a "social media" forum like this often gets you
some right answers and many WRONG ones and you end up looking it up yourself anyway.

What I said was NOT rude, demeaning or unfriendly.
It WAS a basic, simple answer.

Some folks here need to lighten up a bit.

 

How long after starting out does it happen, or what other conditions are present (ie: passengers, packages, rear seats folded down, pets)? My wife tried sitting in the back yesterday for a brief ride to the store and left the belt unbuckled. All three lights and symbols stayed lit for a short time and then went out. I may have disabled the rear seat warning when we first got the car since we don’t usually have any passengers except our large shepherd and didn’t want to be buckling and unbuckling the seat belt every time we carried her with us.

 

Wanted to correct this after seeing the display in my car for myself. The square, left, and right triangles below the seat belt icon identify the center, left, and right seats. This annunciator panel has static illuminated warning icons (so called idiot lights) and the LED clock. If the battery load-tests OK, I would then proceed to removing the lower portion of the rear seat and checking the positioning of the seated occupant detector if possible. You might have to find and download the instructions for this. The rear door switches if not properly operating would provide a "door open" warning on the dashboard, so unless that happens I wouldn't suspect a problem there.

 

What am I missing here? From the info the OP provided I’m still trying to determine if there is an actual problem, yet your advice is to start doing some major removal work? So I am assuming I didn’t pick up on something.

 

From what I read, the OP is reporting a random appearance of the rear seat seat belt power on test display which is all three icons (right seat, center, and left) illuminated at the same time. I would imagine in a properly functioning system if there were occupants in the back seat and one of them was not belted then only that seat position would illuminate. It is also probably true that a marginal charge capacity of the 12 volt battery, which might be six years old if OEM, or connection problems of the battery to ground could be causing a reboot of the ECU that monitors the seat belt system which could trigger that three icon display at times other than when first starting up. The easy check would be to have the battery tested first. The jazz about yanking the back seat out would probably be something I would do in a quest to discover quickly what might be causing this intermittent problem. Could be some shorting of signal or power wiring to the seat sensors. Could be a loose wiring harness connector from the sensors to the ECU. If I were really having this problem I would likely consult with my Toyota service department.