Cab LED added to Interior Light Circuit via control switch.

The simple circuit is LED's placed in the footwells, power (+) to these are T tapped to blue wire of the interior light circuit. From LED's to the switch to allow On/Door/Off. From switch to the interior light circuit ground control. (ILE)
The switch is the same as the Bed Lamp, except it installs vertical. It uses the same connector as the Bed Lamp Switch also. If the OEM Tundra switch is too expensive, a substitute On-Off-On switch will do same job (SPDT)
The fused power is from the tapped cab interior light circuit (7.5A) This tapped circuit stays "ON" since it also supplies power to the vanity lamps, but the system runs a timer when left ON after shut done. (20 min) to "prevent" battery drain. There are other settings for this circuit in the Head Unit.The ILE part of the circuit is what's tied to the door switches (-) providing ground for On n Off with doors opened n shut.

 

Reference (simplified) circuit from a Tundra:

Notice the overhead interior lamp switches only provide Door or ON, the dash vertical switch provides On/Door/Off.

 

Foot well LED can be like the ones here:
https://www.tacomaworld.com/threads/adding-oem-white-console-lighting-elsewhere.622088/

 

Another manner:



A-Pillar harness (IN1 connector) tapped for Dome Cut Relay input to relay coil side. If left ON system powers down after 20min*. For those without the sliding roof, the 20 amp circuit wire terminates at bottom of IN1, an added wire with fuse holder routed to relay pin 30.
The switch to handle ON/Door/Off of the added lamps is same as the Deck Lamp Switch but from a TUNDRA.(vertical) or use your choice SPDT switch.
It's like having dual Deck Lamp switch.
Added lamps are ON with unlock/door open. Off at door closed/lock. And ON if vehicle is OFF*.
(A)@MESO, @DSIM & (B)@KTJO 4x4 , @lapoltba have the needed harness (x2).

 

This be the Cargo Lamp Switch "TAP" harness...

 

It’s a work in progress, but it’s getting there