# TAZ 4 **URL:** \ **Category:** Software\ **Created:** [May 8, 2017, 11:56pm UTC](https://forum.lulzbot.com/t/taz-4/4872 "2017-05-08T23:56:13Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![inventabuild](https://avatars.discourse-cdn.com/v4/letter/i/c89c15/32.png) [@inventabuild](https://forum.lulzbot.com/u/inventabuild)\ **Post date:** [May 8, 2017, 11:56pm UTC](https://forum.lulzbot.com/t/taz-4/4872/1 "2017-05-08T23:56:13Z")
I upgraded my TAZ 4 to a TAZ 6 using the OHAI Kit instructions. I loaded the TAZ 6 dual extruder firmware. The end stops status always stays the same regardless of whether I manually trigger them or not ![End Stop Status Stays The Same.JPG](https://us1.discourse-cdn.com/flex020/uploads/lulzbot/original/2X/0/0a21975b58cecbb5d9839fd505ac203a6a44379e.jpeg) Also, the control box fan runs at twice the speed when I try to move the x, y or z axis via the lcd and the axis do not move. Are there some firmware changes I need to do when upgrading from the 4 to the 6? Any ideas why the end stop status does not change? ---
**Author:** ![piercet](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/piercet/32/12_2.png) [@piercet](https://forum.lulzbot.com/u/piercet)\ **Post date:** [May 9, 2017, 8:43pm UTC](https://forum.lulzbot.com/t/taz-4/4872/2 "2017-05-09T20:43:38Z")
If the endstop always says open or triggered regardless of the current endstop switch position, you have a short or a missing electrical segment. Easiest way that happens is if the control box runs got swapped somewhere, ---
**Author:** ![kmanley57](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@kmanley57](https://forum.lulzbot.com/u/kmanley57)\ **Post date:** [May 10, 2017, 2:51am UTC](https://forum.lulzbot.com/t/taz-4/4872/3 "2017-05-10T02:51:29Z")
If you place the carriages in the center of their travel you should have no triggers of the end stops. But the Z max trigger tells me you have a wiring error be it a wrong switch leads connected to or wires wrong.