1997 Cadillac Catera 6 cyl Two Wheel Drive Automatic 77000 miles. The driver side heater blows cold air but the passenger side works fine. A noise is heard behind the radio console when the car is shut off. It's 15 degrees here and I need heat.
Is there a coolant leak? If not check the heater control valve it behind the the intake by the firewall. Check the vacuum tube to it if its not broken replace the valve. If the valve is leaking, coolant will be all over the transmission, its orange in color.