...fix'd spd control, not on heat? I replaced resistor that did fix the setting of speeds on a/c however it does not work on the heater. I hear it blowing but no hot air thru front vents. Defroster seems to work ok. Is there a door/ flap that is operated by a vacuum? Van has less that 70k miles. I tried replacing the blower motor speed switch before resistor but it made no difference. How do I get to it (vacuum hose or door). Not listed in manual. Thank you for your time! : )