We had to drive around yesterday. The temp was in the thirties and slowly dropping into the twenties overnight. As we rode, the cabin vents put out no air below the dash. Most of the air blew against the windshield and it was not especially warm. My first thought was to change the cabin filter, figuring there must be a clogged old one. Turned out, 98 Rangers have no filter. It is likely a vacuum leak, but could be electrical. I went out and located the parts described on a website about car repair. Saw nothing obvious, then got the hell back inside, where it's warm. By the time my mechanic opens for business next, the temps will have moderated. In fact, 75 is forecast for a few days from now. Well, I will call the mechanic and get an idea what he thinks about it and how expensive it might be.