Re: Heater vents
Reply #7 –
Not sure about ATC, but manual systems control the output with vacuum actuators attached to the flaps, controlled by a sliding multi-port air valve on the back of the heater panel. If you've been working in there (like changing a radio) and dislodged the connector, the valve won't be able to direct the vacuum signal to the proper actuator. You could also have a leaking vacuum line to/from the valve (hear any hissing under the dash?), or a damaged vacuum reservoir (hiding inside the right front fender) or line.