My 2005 X350 has a headlamp fault, Driving home last night my high beam on both lamps wasn't working, however if I used the control to use the headlamp flasher it would work. Today I have noticed that my headlights (not main beam) and sidelights illuminate irrespective of the the control switch. Normally I have the switch on auto but I moved the control to the off position and the lights would remain illuminated.
Normally when the lights are on the dashboard illuimination is dim but last night the dash glowed like it does if the lights are turned off.

During 2017 I had to have the offside headlamp/sidelamp (UK) replaced due to heavy condensation inside the lamp which resulted in corrosion of the connections. 3 months later the headlamp failed and further corrosion was found but this was rectified.

Any advice gratefully received