Keep radio on for 2 hrs after engine is shut off?

My wife and I like to frequent a local drive-in movie theater which puts sound through a common lower band FM radio frequency (i.e. ~88.1 mhz). I have a 2006 Tacoma in which I installed a 750W inverter, which required running 4 gauge wire directly from the battery+ terminal to a 300 amp ignition switch (all grounded to chassis, and safely fused, of course). From that terminal I wired an always-hot cigarette lighter style 12v power source, also grounded and fused. From this I have powered a homemade "boombox" that I made from a cheap car head unit (Pioneer) and four cheap 8 inch speakers (Kenwood) set in oak plywood.

This setup works pretty well for the Tacoma, and we can easily watch a 2 hour movie without even coming close to draining the battery (the truck is currently on its second battery in its 15+ year existence).

I was hoping someone might know if there's a simple way to keep a 2021 4Runner's radio on for up to 2 hours or more without interruption? I'd like to take it to the drive-in and use the stock radio since there are speakers in the hatch lid and the sound system isn't all that horrible. If not possible, is there any way to keep the 12V power outlet associated with the 400W inverter on for more than 10-15 minutes without hard wiring to the battery? Thanks in advance!

P.S. Pic of "boombox" from 5 years ago (can't find any recent pics), if anyone is interested...

 

There’s a way to wire the under-dash fuse box with two fuse taps to power all 12V outlets with power, on the 2019 MY and below. I don’t know if anyone has posted details for the 2020+ models. The fuse box layout changed.

 

Am I missing something? If you leave it in accessory mode, it keeps the power on to the radio as long as you want, or the battery runs out.

 

On my 21 SR5 Premium, the radio shouts down in Accessory mode after a set period of time.

 

Thank you, I'll look into this.

 

This is the idea for up to MY 2019. Food for thought.
Post #17.
https://www.4runners.com/threads/rear-12v-outlet.18459/#post-221350

 

Everything shuts off after 10-15 minutes (not sure exactly how long).

 

Just went out to the garage and took some photos. There seems to be a lot less blank fuse locations than previous MY's and the layout is definitely different. If the blank location is always hot though, the same concept would work pretty easily. I'll check it out tomorrow with the multimeter and update this thread. Thank you for the advice!!

<=2019 (from your post)


2021

 

Is this a new thing? My 2013 has stayed on for over an hour and a half when I left the radio on while I worked on it.

 

One more nanny feature.
Probably a feature of keyless ignition etc.