1984 A/C Blows From Defroster & Controls Are Wonky
05-26-2017, 11:09 AM
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1984 A/C Blows From Defroster & Controls Are Wonky
I've searched the forums and found a lot of posts about A/C blowing through the defroster, although I've seen very little about the '84 with the mechanical slider controls. I have a number of issues I hope to troubleshoot.
1. When the controls are set to BiLevel, the A/C blows ice cold and comes through the vents just like it's supposed to.
2. When the controls are set to Normal or Max, the A/C blows ice cold, but comes through the floor and slightly through the defroster. Very little air comes through the vents.
3. When the controls are set to Off, the blower shuts off but the A/C compressor stays on. In order to turn off the A/C, the slider has to be set to Vent.
I already plan to remove the blower motor and clean out the ducts this weekend. And I've read that there is a vacuum controller behind the dash that I hope I don't have to mess with. Has anybody else experienced a similar condition with their A/C system on a 1984?
1. When the controls are set to BiLevel, the A/C blows ice cold and comes through the vents just like it's supposed to.
2. When the controls are set to Normal or Max, the A/C blows ice cold, but comes through the floor and slightly through the defroster. Very little air comes through the vents.
3. When the controls are set to Off, the blower shuts off but the A/C compressor stays on. In order to turn off the A/C, the slider has to be set to Vent.
I already plan to remove the blower motor and clean out the ducts this weekend. And I've read that there is a vacuum controller behind the dash that I hope I don't have to mess with. Has anybody else experienced a similar condition with their A/C system on a 1984?
05-29-2017, 04:25 AM
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I've searched the forums and found a lot of posts about A/C blowing through the defroster, although I've seen very little about the '84 with the mechanical slider controls. I have a number of issues I hope to troubleshoot.
1. When the controls are set to BiLevel, the A/C blows ice cold and comes through the vents just like it's supposed to.
2. When the controls are set to Normal or Max, the A/C blows ice cold, but comes through the floor and slightly through the defroster. Very little air comes through the vents.
3. When the controls are set to Off, the blower shuts off but the A/C compressor stays on. In order to turn off the A/C, the slider has to be set to Vent.
I already plan to remove the blower motor and clean out the ducts this weekend. And I've read that there is a vacuum controller behind the dash that I hope I don't have to mess with. Has anybody else experienced a similar condition with their A/C system on a 1984?
1. When the controls are set to BiLevel, the A/C blows ice cold and comes through the vents just like it's supposed to.
2. When the controls are set to Normal or Max, the A/C blows ice cold, but comes through the floor and slightly through the defroster. Very little air comes through the vents.
3. When the controls are set to Off, the blower shuts off but the A/C compressor stays on. In order to turn off the A/C, the slider has to be set to Vent.
I already plan to remove the blower motor and clean out the ducts this weekend. And I've read that there is a vacuum controller behind the dash that I hope I don't have to mess with. Has anybody else experienced a similar condition with their A/C system on a 1984?
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lucidardor (05-29-2017)
08-09-2017, 06:03 PM
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Just want to give an update for anybody who has a similar issue:
I replaced ALL of the vacuum lines behind the dash. They were all leaking. I had to replace the AC Control box, and could only find a couple in the country used. They are about $250 for a new one, and I'm cheap.
SO... I bought a used one from a salvage yard thinking it would bolt right in. The faceplate was scratched, so I decided to take the faceplate off mine (because my car is immaculate) and put it on the new one... WRONG
It turns out that a 1984 uses a different AC Control box than a 1985-89, and that the '84 version is molded plastic with no removable faceplate. The 1984 AC Controls had different writing on them, and used a different color for the illumination than the 1985-89.
Long story short, I got the junkyard 1985-89 unit to work and replaced the faceplate. It still blew out the defroster, although now the OFF setting actually turns off the A/C compressor whereas it did not before. Smoke test shows no more vacuum leaks, so I traced the problem a bad actuator (the part you were just describing under the dash). Hopefully this helps somebody.
I replaced ALL of the vacuum lines behind the dash. They were all leaking. I had to replace the AC Control box, and could only find a couple in the country used. They are about $250 for a new one, and I'm cheap.
SO... I bought a used one from a salvage yard thinking it would bolt right in. The faceplate was scratched, so I decided to take the faceplate off mine (because my car is immaculate) and put it on the new one... WRONG
It turns out that a 1984 uses a different AC Control box than a 1985-89, and that the '84 version is molded plastic with no removable faceplate. The 1984 AC Controls had different writing on them, and used a different color for the illumination than the 1985-89.
Long story short, I got the junkyard 1985-89 unit to work and replaced the faceplate. It still blew out the defroster, although now the OFF setting actually turns off the A/C compressor whereas it did not before. Smoke test shows no more vacuum leaks, so I traced the problem a bad actuator (the part you were just describing under the dash). Hopefully this helps somebody.