Heater not working

The vents blow air and the water in the hoses going to the heater heat up. We blew air through there and nothing was clogged up. We could find a switch on the hoses, but maybe we don't know where to look. It's going to get really cold here tomorrow and i need to get this fixed. Any ideas on what the problem is????

Is there a smell of antifreeze in the car when the heat is on or is there a slimy film on the windshield?

No, neither one. It just blow air that is the same temperature as the outside.

The reason I asked that is I was thinking the heating core might have gone bad. Only other thing I could think of would be the thermostat.

Be very careful- take it to a mechanic quickly. The same thing happened to my 91. A gasket went, my coolant leaked out, no heat frmo the heater. Car overheated, warped the head, blew the head gasket and the water pump. Big bucks. No heat because no hot water is circulating through the core.