I actually just ran this exact scenario by a buddy of mine over at KONE Tech Support. He mentioned that on these TM220 harmonized controllers, this specific symptom usually points to a synchronization issue with the safety/aux brakes.
Since there are two of these brakes on the unit (one on the left side and one on the right, both sharing the same name), they both need to pick at the exact same time. For the controller to latch an UP call—and to allow a DOWN call at all—the microswitches for both the left and right aux brakes have to activate simultaneously.
If those switches don't activate at the same time, the controller won't latch the UP direction and it will completely lock out the DOWN direction.
Try testing the aux brake micro switch timing by pushing in the K3.2 relay and testing the timing/activation of the switches.
Last edited by Maxwell; 04/14/26 09:36 PM.