heater&defrost doesn't work

[GirlsLoveDirt]

hey guys when i turn my heater on i hear the blower working but no air is coming out of the vents at your feet or at the front window. I look around and look like a vacuum controled motor and pushed it back and forth sounded like it was moving a flap but i was checking if the air was coming out, It did nothing ? and when i push the defrost-heater buttons i don't hear the fapper working like it use to last winter? what the heck could this be ?

[Wart Hawg]

Could be one of the three vacuum lines that hooks up to the controls has a leak in it or has disconnected itself. Had that prob on mine.

[Chero77]

Ok, there are two doors, each being actuated by a seperate vaccum motor, on the FSJ heating system. The first door is normally closed and it prevents air from the blower from passing through the firewall into the interiour ducts. It sounds like the vaccum motor which operates this door is not working on your vehicle. The vaccum motor for this door is located on the main air duct on the passenger side of the vehicle. Its easy to get on non-AC equipped vehicles, but may be blocked by the AC evaporator housing on an AC vehicle.

The second door is in the floor register. It just flips between floor heat and defrost. This is not your problem because even if the vaccum motor was not working you would still have floor heat.

Beaware, that the vaccum lines from the heater control unit make a 180 degree bend from the control unit and then run under the dash to the two vaccum motors. It is not unusual for these hose to break or tear where they connect to the control unit. Also the black ball (vaccum storage tank) on your vehicle may have cracked.

[ October 02, 2003, 05:16 PM: Message edited by: Chero77 ]

[GirlsLoveDirt]

if that happen " crack in black ball " would the 4 wheel switch and cruise control not work ?

[firechero]

4 wheel drive switch is on seperate vacuum lines, ive had exact same problem with my heater. pull out your instrument cluster and make sure 3 rubber vacuum lines are hooked to heater control. if u hook em up wrong u just have the heater switch blowing the defroster and vice versa ;)

[GirlsLoveDirt]

yeah i checked that already i got a nogo everything looks new and in place i think the previous owner replaced a bunch of stuff under there