Help high pitch whine from dash!

Hey. There is a high pitch whine coming from the dash somewhere as soon as my truck turns on to when its shut off. It persists while the engine is running and while I'm driving, always constant and never wavering. It is VERY annoying and I can't for the life of my think of what it may be. I have tried switching out the fuse for Room, but to no avail. When I remove this fuse completely the noise slowly dies off, but then none of the electric features such as indoor lights will run either.
Any suggestions will be more than appreciated as this whine is driving me crazy.

Edit: The truck is a 1992 b2200 base model with 194000km.