Why does your 1998 grand marquis blow just hot air?

If your 1998 Grand Marquis is blowing only hot air, it could be due to a few common issues. One possibility is a malfunctioning thermostat that is stuck in the closed position, preventing coolant from flowing to the heater core. Another potential cause could be a faulty blend door actuator, which controls the air mix between hot and cold. Additionally, low coolant levels or a clogged heater core could also lead to this problem.