2018 PP+ dome light switch

I'd start by replacing the bulb.

 

Yeah, if the car is still under warranty, and you don't mind stopping by a dealer, then let them take care of them. If it is out of warranty, then that would be a different story. Then I would try to fix it DIY before taking it anywhere. If DIY, first check the voltage coming from the bulb socket when it's on and off. If it is coming on and off intermittently like the light, then yeah, there must be some discontinuity in the switch or wire. I have no idea how hard it can get, but if it is just a simple loose contact point of the bulb, then it may be fairly easy to fix?

 

Did you ever sort this out? I am having the same issue. Don't know how I missed this in my initial search.

 

I too have been having the same issue on my 2017 Prius Prime Advanced for about 6 months. It is not a loose or malfunction bulb because both dome bulbs will turn on when I manually turn it on.
With the door in the proper setting, the interior lights are supposed to turn on when the door opens. If I have the door open and push on the dome panel around the switch, I can make the lights go on.
Is the switch replaceable or is this only available by replacing the entire front dome?

 

I have the same issue in my 2017 Prius. The bulbs themselves work fine when I turn the switch to the "on" position. But when it is in the middle, on "door", the lights do not come on automatically as they should. Twice now I have pried off the cover, pulled out the switch and cleaned it off. When I put it back in, everything works as it should for a time, and then it stops working again. So, it would appear that the connection is getting shaken loose somehow.

If anyone has had this fixed or knows how to fix it themselves, I would love to know about it! It's hard to believe that in 2022 something as simple as a light switch is failing.

 

I have a 2017 Prius Prime. Same issue. It comes and goes. The fix is replacing the map light assembly. The part lists at $200USD, but ordered online from Toyota is closer to $129. You need a device like a trim puller, which is a mini-pry-bar. You pull the assembly off, unplug it, pipe it back on. Piece of pie. There are videos on the web.​

 

You can actually do some maintenance on the switch itself, I followed a procedure on the youtube video with ID# ETv0WX4BsX0 (can't post links sorry) and also squeezed the contacts a little to apply more pressure, and replaced the dielectric grease. For $198 cheaper it's worth a try.

 

I have the same issue with my 2018 PP. Sounds like an engineering problem with this design. Has anyone figured out how to fix the switch rather than replace it with one that will also fail?