Heat stuck on vents
11-21-2010, 05:14 PM
#1
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Car: 99 Formula
Engine: LS1
Transmission: T56
Axle/Gears: 342
Heat stuck on vents
Did a search and most people seem to have their heat stuck on defrost as it's the default setting when something is wrong.
However, mine is stuck on the vents. Anyone know which color vacuum line controls the defrost setting?
However, mine is stuck on the vents. Anyone know which color vacuum line controls the defrost setting?
11-21-2010, 09:40 PM
#2
Re: Heat stuck on vents
Mark,
Long time...
The dash vents get air from the system upstream of the defrost and floor outlets. If both the dash outlet dampers are open no air will get to the defrost/floor section of the ductwork.
The red hose opens the upper dash outlet damper. If only the upper damper is open the mode is "Bi-Level" to distribute some air to the dash outlets and some to the floor outlets. The damper actuator is spring returned to the closed position.
The tan hose opens the lower dash outlet damper. If both the upper and lower dash outlet dampers are open, all air is routed to the dash outlets (your condition). This damper actuator is also spring returned to the closed position.
The blue hose opens the floor outlet damper, closing the defrost outlets. It is a spring return to default to the defrost outlet position.
The orange hose operates the recirculation damper. It is a spring return to default to the fresh air position (no recirc).
It sounds like the dash outlet dampers have vacuum when they shouldn't or the dampers are mechanically stuck open. If there is vacuum on the red and tan hoses, the ported vacuum control valve may need attention.
Long time...
The dash vents get air from the system upstream of the defrost and floor outlets. If both the dash outlet dampers are open no air will get to the defrost/floor section of the ductwork.
The red hose opens the upper dash outlet damper. If only the upper damper is open the mode is "Bi-Level" to distribute some air to the dash outlets and some to the floor outlets. The damper actuator is spring returned to the closed position.
The tan hose opens the lower dash outlet damper. If both the upper and lower dash outlet dampers are open, all air is routed to the dash outlets (your condition). This damper actuator is also spring returned to the closed position.
The blue hose opens the floor outlet damper, closing the defrost outlets. It is a spring return to default to the defrost outlet position.
The orange hose operates the recirculation damper. It is a spring return to default to the fresh air position (no recirc).
It sounds like the dash outlet dampers have vacuum when they shouldn't or the dampers are mechanically stuck open. If there is vacuum on the red and tan hoses, the ported vacuum control valve may need attention.
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