While we haven’t specifically included firmware or install directions for the v3 dual extruder on the TAZ 4 some of our more advanced users may want to try their hand at making it work! Below you can find a brief overview of how to get this up and running for people who want to give it a shot.
As this tool head is all set up for a TAZ 5, the easiest path for using it on your printer is to upgrade your TAZ 4 to a TAZ 5. The only major difference between the two versions is: the 5 came with an all metal hot end, PEI on the bed, internal wire harnesses to support the extra cooling fans for the all metal hot end, and a different connector for hot ends for ease of use.
First things first, you will need to install two internal wiring harness for your controller box. They can be purchased here: https://www.lulzbot.com/store/parts/internal-blower-harness-add (If you have already installed a Hexagon hot end upgrade, you will only need one additional harness.)
Wiring harness for Extruder port 1 directions can be found on step 9 here: https://ohai.lulzbot.com/project/taz4-hexagon-toolhead/accessories/
Wiring harness for extruder port 2 directions can be found here: https://ohai.lulzbot.com/workflow/prep-taz-4-second-extruder/accessories/
Next install the updated tool head harness to match the v3 connector pins. This is a simple screw in to the controller box, and will allow connection to the extra fans on the tool head. This can be purchased here: https://www.lulzbot.com/store/parts/lulzbot-taz-5-v2c-tool-head-harness
Those are the only hardware modifications required! For getting everything else set up, follow through with the TAZ 5 and TAZ 6 install directions in the OHAI kit here: https://ohai.lulzbot.com/project/lulzbot-taz-dual-extruder-tool-head-v3-install/accessories/
When flashing the firmware, be sure to use the TAZ 5 firmware. With the hardware changes, you’re now rocking a TAZ 5!
As a note, when setting up Cura you can re-name your Machine to a TAZ 4 v3 Dual Extruder to prevent confusion.
We hope this helps!