The heater stopped blowing on my 98 Olds Intrigue.

Blower motors generally last about 120k miles(in Minnesota) They have brushes which eventually wear out. As they wear there is less tension on them against the comutator and so it requires more voltage to get them to run. Thats generally why "Hi" on the control is the only one that will make them run close to the end of thier life. This dose not rule out the control itself or the resistors. The resistors are located under the glove box behind the blower. Remove them and visually check their condition. Measure them with an ohm meter, they should all be less than 20 ohms. Remove the control and check it for overheating. Switches like to become resistive and overheat, melting the plastic frame and the plug. If all checks good replace the blower motor. You could check the motor by applying 12 volts to it and it would probably run but now that its removed its been bumped around and the brushes are making better contact. So don't be tricked. Like I said, if it has alot of miles on it (time) your better off with a new one anyway.

No heat in my old's intrigue. I replaced the heater core plus the thermostat. Still no heat! Does anyone have any advice?