I've had my Riv since 1996, and its in pretty good shape. I'm doing some upgrades, and right now there is NO HEAT. I replaced the fuse, but that didn't do it. The HEATER CONTROL SWITCH is reeaaallly stiff and won't move freely. It also doesn't want to go all the way to the right. The heat, defrost and vent used to all work well. Over time, it stopped. My question is what should my plan be?? How can I tell if the switch still works, or if it just needs some WD-40? After that what other things should I look out for? I think the fan blower motor works, only saying this because it used to. I'm thinking it has to do with the stiff heater control switch. Any expertise or good advice is really appreciated. THANKS!!!