# Firmware help: Lulzbot taz 3 extruder/hotend upgrade

**URL:** <https://forum.lulzbot.com/t/firmware-help-lulzbot-taz-3-extruder-hotend-upgrade/20316>\
**Category:** Uncategorized\
**Created:** [January 3, 2020, 9:02pm UTC](https://forum.lulzbot.com/t/firmware-help-lulzbot-taz-3-extruder-hotend-upgrade/20316 "2020-01-03T21:02:31Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![HunterTH03](https://avatars.discourse-cdn.com/v4/letter/h/ebca7d/32.png) [@HunterTH03](https://forum.lulzbot.com/u/HunterTH03)\
**Post date:** [September 4, 2020, 12:14am UTC](https://forum.lulzbot.com/t/firmware-help-lulzbot-taz-3-extruder-hotend-upgrade/20316/2 "2020-09-04T00:14:41Z")

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I have made some furthur progress and now I need help with another firmware configuration error I’m getting when trying to set heat sink fan to come on at 50 deg c. I have a Taz 3 which I upgraded with a hexagon hotend. I’m trying to have a part cooling fan (which I already have working) and a 12 or 24V heat sink fan that I can control or that automatically comes on when hot.

I already ran the wiring as described in [this forum](https://forum.lulzbot.com/t/taz4-rambo-aux-fan-wiring/700/27) and am working on the firmware. I made the edit to configuration\_adv as described in the above forum, but I get a “‘FAN1\_PIN’ was not declared in this scope” error in the temperature.cpp page. I never edited this page and I copied/pasted the code exactly as it appears in the above forum. I am using Arduino version 1.0.5-r2. Any help would be appreciated. I can include the exact code if that would be helpful.

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