sterling mirrors

I bought a '94 sterling hatchback last summer. Lovely motor. V6 Honda. It has a few niggles, but what hasn't at nearly 10 years old. It took me to Belgium last week without problems. I do not have a handbook for this car. Today's annoying niggle is the electric mirrors. Dont get me wrong, they work just fine, too fine. Question. How do I turn off the mirror electric heaters? The salt laden crap from the roads dries almost immediately and makes the mirrors virtually unusable. TIA Ian Lowrie