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Thomas A
05-17-2007, 10:37 PM
I'm having a bit of a problem with the HVAC system in a '93 Thunderbird. The problem has to due with the air coming out of the vents. If the heater is on, no matter how high you turn up the fan, there is very little air coming out of the vents. However, if you turn the temp way down and have the AC on, the air blows out just fine. The blower fan is running full speed, so it is as if something is being blocked on the heat side of things. Could there be an issue with the blend door, or maybe something to do with the heater core? The air still gets hot when it's on heat, it just doesn't hardly come out of the vents at all.

Thomas

Tim Groth
05-17-2007, 10:42 PM
I'm having a bit of a problem with the HVAC system in a '93 Thunderbird. The problem has to due with the air coming out of the vents. If the heater is on, no matter how high you turn up the fan, there is very little air coming out of the vents. However, if you turn the temp way down and have the AC on, the air blows out just fine. The blower fan is running full speed, so it is as if something is being blocked on the heat side of things. Could there be an issue with the blend door, or maybe something to do with the heater core? The air still gets hot when it's on heat, it just doesn't hardly come out of the vents at all.

Thomas


Sounds like something dealing with the blender door - my dads F250 had a similar problem when there was a pen jamming the door. Had great AC however no heat...found the pen and it work great.

Had a friend with a Contour and the blender door lever broke so it did something similar...might check that too.

-Tim

Thomas A
05-17-2007, 10:45 PM
Yeah, that is kind of what I was thinking. I'm not too familiar with how these blend doors work. I've worked on Mark VIII ones, but they are quite a bit different. They have a little electric motor with a shaft that tends to break, and you end up with no heat. I'm pretty certain the blend doors on our cars are vacuum actuated, but I don't know much more than that.

Thomas

Tim Groth
05-17-2007, 10:49 PM
Yeah, that is kind of what I was thinking. I'm not too familiar with how these blend doors work. I've worked on Mark VIII ones, but they are quite a bit different. They have a little electric motor with a shaft that tends to break, and you end up with no heat. I'm pretty certain the blend doors on our cars are vacuum actuated, but I don't know much more than that.

Thomas

Yeah it has vac that pulls when you change the options on the head unit control for the setting you want...how it could pull less vac from setting it on heat vs. a/c makes no sense. I would start with the easiest link and replace the controls...if nothing then check the blend door.

-Tim