mobile home dimmer switch

You need to Kill the power, cut the wires, install a cut-in switch box, then install a standard dimmer.

It's called an old work box, looks like this.
Make sure the walls are deep enough to install one before buying one.
http://www.bing.com/images/search?q...C24EDDCC333A8051BCAE1580026412C09D7A8&first=1

Often time mobile homes have paper thin walls.

depth shouldnt be a problem, we have replaced receptacles in two mobile homes and neither had any problem fitting the old work boxes, even the walls made of 1x3's fit without a problem. Not contradicting you, Joe, just my two cents. good luck bill

This one works well for shallow spaces.
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?productId=202077341&storeId=10051&langId=-1&catalogId=10053&ci_sku=202077341&ci_kw={keyword}&kwd={keyword}&cm_mmc=shopping-_-googleads-_-pla-_-202077341&ci_gpa=pla#.UL5Rs4awV7k