My truck only shoots air out of the defroster and only on fan speed 4. I know the fan speed issue is due to a bad resistor.
The previous owner put a new fender on it and said he "forgot to hook up a vacuum line behind it" that controls the directional movement of the air flow.
I looked at the vacuum line under the dash and it seemed fine as did the one near the blower motor under the hood.

What am I missing?

Thanks,

 

there are several little vac lines just keep lokking try useing carb cleaner u might find it easier

 

There's only 1 vac line from the engine to the HVAC controls and it ain't supposed to be behind a fender. Should be over there near the heater box on the passenger side of the engine bay. Supposed to have a check valve in it too I think. If that line is connected, you should have vac at the mode selector in the cab.

 

If you have the metal coffee can looking vacuum reservoir and the passenger side inner fender, you might want to check the bottom of it for rust holes.

 

That metal coffee can looking vacuum reservoir has nothing to do with the vacuum motors in the vent system.

AC Vacuum tank:


Vacuum line and check valve:


Vacuum source:

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exellant pics

 

I checked all my vacuum lines and they seem to be fine.

 

When I shut the truck off, I can hear a "pshhhh" coming from the HVAC controls.

 

There's a vaccume controlled actuator for the vents on top of the black a/c box on the passenger side the plastic vaccum line probly is broke

 

Sounds like you may have a bad vacuum control that is leaking vacuum.

 

After a 20 minute drive. You may need to turn your volume up to hear it.