difficulty removing map light dome. Am I missing a screw?

Your video hadn't ah w up before I posted this one, so fodder.

 

I did pull my slightly different maplight and it just was in tight with no screws. However you should first pull from the bottom half and check for tabs ("claws") inserted on the top side. This is on a Prius v but may be the same on yours.

The sure way is to get a weekend subscription to the toyota information system (tis) and locate instructions on removing it. But sometimes that can be difficult as they may not call it the same thing you might and there is a little learning curve navigating the site. Plus some people's actual pics (eg page 10 of the attached pdf) may differ slightly with the Toyota instructions for your model.

 

The OP has a according to the original post I have the prius V five with tech package....

 

I believe I used a wire tap where you lay two wires in parallel and press the assembly closed. Available at hardware and auto supplies... use the appropriate size for your wires

 

You probably need to get into that bigger cable on the top of the pic that feeds the whole map light assembly. For one thing, the possible power and ground on the pc board connectors a & b may be limited because of the size of the pc board traces feeding them.

Always check with a voltmeter first in any case and be sure of the power you want, eg switched 12v only when the car is on or unswitched 12v, always on.

The best answer is through the Toyota TIS system which costs around $15 for a weekend and provides download capability.

Here is a version of the maplight wiring found on an autosupply website. Note that UL1 is NOT at the maplight. The connector on top should be a 20 pin with 11 and 1 as unswitched +12v and 15 and 10 for ground. In other words, disconnect the big cable and find the pins by looking at the end of the cable's connector. And then verify with a meter.

If this is not make sense to you, private message me.

 

I believe trim 5 will have switched 12 up there somewhere, probably for the homelink system which usually has switched and unswitched. If its on the twenty pin connector, it is likely to be on pin 8, 9, 12-14, or 16-20, all of which are unused on a v3.

People I know want the camera on when parked. Some will install a small lithium ups to ensure continuous power for the camera when parked and charge it with switched 12 while driving. I have seen 12v ups for around $33 on Amazon.

Linked below is a factory procedure for installing a homelink mirror on a 2015 Prius v. They run power from the under dash area to the mirror. So if you have a factory homelink mirror, just tap one of the wires up there near the mirror.

Otherwise you have the step by step on how to get switched 12v by tearing things apart. If you were to add a lithiun backup, it could be installed down at underdash area and feed the mirror and the camera. By the way my added homelink connected to 12v at the maplight draws 6 ma constantly. I still have my seven year old factory 12v battery.

http://www.trdsparks.com/install/00016-05463-PRIUS-V-inst.pdf