Rover 214 strange problem with lights and demister?

i have a wierd problem with my rover 214 when i turn the headlights on the rear demister turns on and will not switch off. Also i have to turn the rear demister on to have lights on my dashboard at night. When i press it the clock also dims. This just started a couple of weeks ago?! Can anyone help me please ?! thanks!|||my answer is try to go on auto repair shop then you will check it out first