2005 Prius Brake LED lights not working properly

Sorry I don’t really understand you.

Other lights work fine? Brake lights light up when pressing the brake and stop lighting when not pressing the brake?

Isn’t that exactly how they are supposed to work?

 

I think he's saying all the brake lights work except the 3rd light. Never seen that before only the third light failing. lets see if the OP come back.

 

There is a brake light switch that contacts the brake pedal to activate the lights. I think it may be either not working or just out of adjustment.

 

The most obvious cause of this is: Not turning the lights ON......and driving with DRLs only......or no lights at all.

I have been guilty of that occasionally, since one of my cars has automatic headlights and the other one (Prius C) does not. But the DRLs are pretty bright in front.

How old is your Mom ??

P.S. The lights that you are talking about are called "tail lights". The 3rd high mounted one is a brake light only.

 

I still don’t understand.

That’s exactly how they are supposed to work. They are called brake lights they turn on when pressing the brake. Did they work differently in the past?

 

No they aren't. He is talking about the TAIL LIGHTS.
Please read all that he has posted......and think about it.

 

I don’t think so:

That clearly says that he thinks that brake light is supposed to be on without touching the brake pedal.

And:

That says that taillight do work.

 

And I think that you aren't thinking.

He is obviously using the wrong terms to describe the problem.

 

Yes. I understand that. I just don’t understand how did you come to a conclusion that it’s the taillights that don’t work?

There seem to be two things contradicting that conclusion. First he says that taillights are working. What could he mean by that? And second he does think that 3rd brake light is supposed to light up without braking. What could he mean by that?

 

Yes.
So what isn’t working?

If you turn the light switch on you should get (on the rear end) taillights and license plate lights. If you step on the brake you should get the brake lights (on bough rear lights and the center brake light).

 

We don't KNOW without actually SEEING what is happening........because your description is so confusing.

And for the second part...........OK, because I don't think that your other Pruis does that either.
But then I'm not sure WHAT IT IS that we are talking about.

When you turn on the parking lights or headlights, SOME of the red lights on the rear of the car also come on. Those are TAIL LIGHTS........and usually do NOT include any of the "3rd light bar".

Then.....when you step on the brake pedal, some MORE red lights on the rear come on or get brighter, including the 3rd light bar. Those are BRAKE LIGHTS.

BRAKE LIGHTS do NOT come on with the headlights.

 

He’s just messing with us.

 

Nah, he's giving us all the information we need, and we're trying so hard to sound smarter than the OP that we're skimming right over it.

He's looking at a 2005 and wondering why it doesn't light up the same as a 2010. Well, here's why:



The Gen 2 introduced the bounce-LEDs-off-reflectors idea for the brake lights (up in the top chamber of the combination light), but still used a conventional incandescent (separately, down in the bottom chamber) for the tails.

For Gen 3, they liked the bounce-LEDs-off-reflectors idea so much that they got rid of the separate incandescent taillight, and 2010 and 2011 just uses the same bounced LEDs in the top chamber for brake (full brightness) and tail (reduced brightness).

The OP was surprised that the 2005's brake LEDs don't light up at partial brightness as taillights ... which is because it has its separate, incandescent taillights ... because it's a 2005.

... and of course the center brake light is only ever a brake light, on either model.

-Chap

 

Are you then going to take the incandescent taillights out? What will you do with the empty space?

-Chap

 

Sounds like an illegal modification as then your brake lights would be on when you’re not braking. Like
ChapmanF said. On gen 3 that upper light is bough brake light and tail light. So it is approved as a brake light with full brightness and as a tail light with lower brightness. On gen 2 the upper light is approved as a brake light with full brightness and the lower light is approved as a parking light with incandescent bulb. Why do you want to do this modification anyways?

Doing the modification would actually be pretty easy with just resistor and couple of diodes. And would require very little disassembly.

Does the third brake light really come on, on your gen 3 when not braking?
That was the thing that was confusing me. Also all the people that just started guessing didn’t help.