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· Premium Member
168 Posts
Discussion Starter · #1 ·
Hello everyone. Slowly troubleshooting no heat issues and noticed a potential separate issue.

Regarding the air diverter valve or diverter door?? Not sure of the correct name.

Currently Air comes out as follows with the following HVAC knob selections::

Max:: Out the front (only)
A/C:: Out the front (only)
B/L:: Both Front and Top
Vent:: Out the Front (only)
Heat:: Out of the Top (only)
Blend:: Out of the Top (only)
Defrost:: Out of the Top (only)

Are these correct??

If some of the positions are correct and some aren't, is this typically a vacuum line issue or a diverter door issue? I can hear some "wooshing" and "swishing" as I'm moving the knob back and forth but I'm not sure if I have a half-a$$ed vacuum issue or a half-a$$ed diverter door issue. I plan to ultimately try to get to the diverter door itself to look for blockage. But was hoping for vacuum/troubleshooting help in the mean time.

Thank a bunch.


· Registered
3,118 Posts
Air Control Knob
OFF: The system is off.
MAX: Upper air vents only (aka recirculate).
A / C: Upper air vents.
B / L: Both the upper air vents and the heater ducts.
VENT: Upper air vents.
HEAT: Mostly through the heater ducts, a little through the windshield defroster vents.
BLEND: Both the windshield defroster vents and the heater ducts.
DEFROST: Mostly through the windshield defroster vents, a little through the heater ducts.

AC compressor operates in MAX, A / C, B / L, BLEND, & DEFROST, but not in VENT or HEAT.
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