2012 Highlander all 12V power outlets dead; fuse is good and not the issue. Where and how do I check relay? There is NO debris in the outlets

It is possible that the issue with the rear power outlet not working on your 2016 Hyundai Sonata is due to a problem with the power outlet relay in the engine fuse box compartment. You should inspect the relay and see if it has any visible damage or if it is loose. If it is damaged or loose, you should replace it. If the relay looks fine, you can check for any other fuses in the engine fuse box that may control the rear power outlet. If you are not familiar with electrical systems, it is recommended that you take your vehicle to a qualified technician for further diagnosis and repair.

This fuse box diagram show a power outlet fuse in the inside fuse box. It also shows two fuses and a relay in the engine compartment fuse box.
https://www.autogenius.info/hyundai-sonata-hybrid-2017-fuse-box-diagram/
The relay says for 3 power outlets
One of the fuses says for cigarette lighter
If all the fuses are good the outlet which does not work may have shorted and blew the fuse. Check outlet to see if it has power to it.

The fuse for the console outlets is a 20 amp fuse #33 in the fuse block. There is a relay involved and a 10 amp fuse for the control side of this relay. It, the fuse, is #19 in the fuse block. Check both fuses as either can make the circuit not function.

Check the fuse in the instrument panel junction box, left side of dash panel. Tan color box, power outlet 1 or 2 15amp fuse.

check the fuses under the dash

my guess, its a dead horn? both dead?
no actual question asked????????
the fuse is blow? in fuse box, eng. bay box.?
if no power to horn, (voltmeter)
we check power in and out of relay if there is one.
then at the horn button wire, (air bags can kill any mech. defeat them
first if heck bent to fiddly steering column parts in any why)
all this info is convered in in the FSM, get one. or login to alldata dot come. and read it.
here, ill look at yours. now.... a fast look.
ok 2 horns, hi/lo, and 1 relay in the under hood fuse box.
it should be labeled in the box, HORN
the relay can not work if the fuse is blown
or the horn enable line is dead. button.
the button grounds (0v) the relay via wire color lt.green-blu pin a11 on relay. if the a11 is at 12v the fuse is good.
if you push the horn button this A11 goes from 12v to 0v, and the relay energizes (click) and the horns both blow.
if no power makes it to the horns, the relay is bad no 12v
if by chance the relay output to horns go to 12v, then the horns are both dead.

Could be debris in the socket of each outlet. You would need to gain access to the back of the sockets to check for power and ground.
Keep in mind you may have a fuse for the outlets and another for the actual cig lighter.

there is a fuse/junction block under the left side of the dash, you need to replace the Acc. Sock. fuse 20amp

first thing you should check is for debris in the outlets. 99.9% of the vehicles we see with this problem have debris in the outlets.

You have a blown fuse that controls that circuit. Look for the POWER OUTLET fuse under the dash, and replace it.