Interior lights do not go on

Check the switch on the middle front of the ceiling. It needs to be in the middle position. One side is On, the other is Off, the middle position is on with doors open.

Failing that, it could be the fuse, but I think that feeds the lights under the doors too and maybe the switch illumination.

SM-T813 ?

 

There's a similar switch on the light over the back seat.

 

You mean the door button that pokes out from the door jamb in its little rubber boot, right?

Those things are often dead simple. Your problem certainly isn't a short (that would make the lights be on most of the time, or would blow a fuse or make bad smells). It is probably just poor electrical contact in the switch.

That could just be oxidation, on a ten year old car in a humid state.

Usually with that kind of switch if you take it out you can see right away what to clean so it works right.

 

He said it's a Gen4 - 2016. I've had them go bad in that time before. As ChapmanF says, they're often an easy clean - in older cars it was just an earth return - which only connected with the door open. Used to be like this - run some wet/dry through the contacts and it works again. One screw to undo, hidden behind the rubber cover. Pull the fuse first is probably a good idea - at least I should suggest it, even if I may not do it myself.

 

Or you could swap it out with the passenger side one.

 

You said the lights don't come on when the "doors are" (plural) open. It seems unlikely that all five door switches have corroded, assuming as you said that the switch is in the right position. And as @ChapmanF very accurately pointed out, there's no way it could be a short and the fuse doesn't seem right either. That leaves the switch on the front dome light. If the regular Prius is like my Prime, the switch on the back seat light does not have an "off" position; just "on" and "door."

Those switches always look to me like something someone cobbled up out of scrap. Most likely, you can take it apart and clean it up. It might take a little fine sand paper and some slight bending to get a solid contact again.

 

I just went out and checked - only 2 positions on mine too. But then - I only ever go in the back seat ... with a vacuum cleaner occasionally.

 

Same here. I had to go look for that same reason.

 

FWIW The rear interior light, when switched to the "door" position goes off when you switch the front one to the "off" position.

 

Ahh - I'll keep that in mind next time a Grandchild dabbles with it. Though - I told him off when he did it - last thing I want was to discover it had flattened the battery.

Odd chain of events. I was driving 4 of them home from school and saw "A" reach up to the light while stopped at the traffic light. I said to turn it back to door. He didn't understand - but fiddled with it again. I opened my door to check it was on door - yep, OK. Waited for the traffic light to turn GREEN - then hit on accelerator. NOTHING. Quick think. Stupid thing had taken it out of "D" when I opened the door. GRRRR.

 

If they switch the rear one to "ON" it will stay on even if you switch the front one to "OFF"

 

Ahhh!! I think they're supposed to turn off after 19 minutes anyway - or at least my KIA used to.

But when I had the KIA - which turned lights off after a reasonable period, we had a TARAGO/ESTIMA/PREVIA at work - with at least 5 interior lights - and children on board EVERY day. Which DIDN'T turn them off ever.

And so it had flat batteries quite often - at least monthly or more often. The car was parked every afternoon in a very bright location - so it wasn't obvious to the drivers - who had a lot more on their minds than "are the interior lights off". Was quite annoying. I suggested we should take all the bulbs out - but they pointed out that the vehicle was used for after-hours call-outs. Oh, well.

 

Curious... Mine doesn't do that. It just makes a continuous beep and displays "Shift to P before exiting vehicle".

SM-T813 ?

 

same.

 

OK - I'll go do a "grand-children-less" test when I'm out next.

 

I tried looking to see if this resolved the problem with the interior light but I’m not seeing it. I push up on the switch and the light comes on but I let off the switch it goes off again. Any help would be appreciated.
2016 Prius

 

Which switch are you referring to, the the one in the center front?

 

The light switch on the ceiling between the driver & passenger seats.