I have an ETSL error 97 xtra 230919. I replaced the CEDES ETSL 1 and 2 optical switches and the CIO board.
With the car at the bottom landing, ETSL 2 LED is on and ETSL LED 1 is off. If I switch CIO X10-4 and X10-6 there is no change in my LEDs. ETSL 2 LED is still on and ETSL LED 1 is still off.
