Proper vent operation
Thread Starter
Instructor
Joined: Mar 2004
Posts: 138
Likes: 0
From: Naples FL
Proper vent operation
My 88 with climate control has had very weak airflow since I bought it. This evening, following the excellent instructions here, I replaced blower motor with little trouble. Doing so helped my air flow. Not quite as much as I hoped but it is definitely better and when I go through the different fan speeds it actually changes the amount of airflow when before it didn't. My question is when you have it set to the AUTO ac setting, should all of the air be blowing out the dash vents? In my car there is a significant amount of air coming out of the defroster vent at the same time. If I change the setting to defroster, the dash vents stop and it all goes to the defroster but if I go back to AUTO, there continues to be a lot of air coming out the defroster. If this is normal behavior, oh well my bad, if not, I'd like to see if I can fix it because if the air coming out the defroster was pushed out the vents, I think I would have much better cooling in the vehicle.
Instructor
Joined: Dec 1999
Posts: 209
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Duf, The A/C-Defrost door is a 3 position door. In Defrost setting, all air is diverted to the defrost vent. In the Bi-level and Heat setting, the air is primarily diverted to the A/C vents at the floor and dash. In the A/C or Vent setting all air is diverted to the A/C floor and dash vents, No air to the defrost... so, it sounds like you have a door that is not moving fully thru is range.
Burning Brakes
Joined: Jul 2004
Posts: 806
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From: Langley B.C.
Originally Posted by fundriving
Duf, The A/C-Defrost door is a 3 position door. In Defrost setting, all air is diverted to the defrost vent. In the Bi-level and Heat setting, the air is primarily diverted to the A/C vents at the floor and dash. In the A/C or Vent setting all air is diverted to the A/C floor and dash vents, No air to the defrost... so, it sounds like you have a door that is not moving fully thru is range.
Advanced
Joined: Oct 2004
Posts: 81
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From: ALEXANDRIA VA
Check My Threads
HAD THE SAME PROBLEM ON MY 94. THE DIVERTOR VALVE BROKE OFF AT THE TIP. CHECK (Shoregasm thread titled what is this? Changed mine now air blowing like a champ from the dash...........................
Burning Brakes
Joined: Jul 2004
Posts: 806
Likes: 0
From: Langley B.C.
The Front and Rear Mode Valves determine wether air flows to the Heater Outlets or the A/C-Defrost Outlets or both. In the HTR Mode both valves are in position B which directs all air flow to the Heater Outlets. In the ECON Mode both valves are in position A directing all air to the A/C-Defrost Outlets. IN BI-LEV the Front Mode Valve is in position A and the Rear Mode Valve is in position B. Air flow is then directed to both the Heater Outlets and the A/C-Defrost OUtlets. When operating in the AUTO Mode the Heater and A/C Control Assembly determines the positions of the mode valves from the exisiting cooling or heating requirements. Direct from the manual. 
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