The D9 (red) and D10 (Green) leds on a UCM must both be blinking continuously for normal operation. These show the RS485 communications. D10 (Green) is the received message and D9 (red) is the transmitted message
If D9 Red led is off it means that the UCM ID is not polled by Comfort. This is normally due to an ID issue. Check the ID of the UCM, and do a Scan for UCMs in Comfigurator
If D10 Green Led is off, it means that the RS485 (KA and KB) signals are not connected to Comfort.