If the lantern blinks (Dims) at the same time as you are commanding the turnout to switch, it is an indication that power is being drained by the decoder.

My guess is the point motor is either binding , or an end cutoff switch is not working properly (cutting out when it shouldn't)

you could try
- verify that the solenoid motor moves smoothly without binding
- manually position the motor at the other end and retry the command to switch it

It may be that the solenoid will only drive one way.

you should confirm the following in your problem description
- Is this for C-Track or T-Track
- have you soldered the lantern to the decoder
- which solenoid mechanism do you have
- whether the solenoid is tested and known to work nativly (without a decoder)
- If you are using an external power source for the "yellow/white" or tapping of the "Red" for power.