Thank you!
The build thread and part STL’s for that particular modification are located here: Add status indicator LED's to your TAZ in the “add status indicator lights to your TAZ” thread. You will need some electronics (you can buy that as an assembly from Makers Tool Works, it’s basically the same one used in the Mendelmax 3 or separatly from other sources), you have to tie those electronics to the I2C pins on your Rambo board (which are currently unoccupied) and you have to tie into power to power the LED’s Then there are a couple of firmware pieces that need adjustment / adding. The firmware files in that thread should work for a Taz 4. i haven’t added my hexagon hotend to my printer yet, so I haven’t finished a Taz 5 version of the firmware yet, but that will be coming fairly soon. I’m just waiting on the extruder fans.
I would rate that project at about the same complexity as installing a dual extruder setup on your TAZ. The modification itself will work and fit on a Taz 3 and up. If you have any questions or need to see details of the installation, etc. let me know!