AC Mod
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Tuned
Joined: Aug 2003
Posts: 278
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AC Mod
I did the air conditioner/heater core bypass mod today. Well almost anyway. I downloaded some instructions awhile back calling out 3/16" vacum line from the vacum tee to the valve switch. Actually I used 3/16" fuel line. However the valve switch plug is smaller. I think it might be a 1/8" so I'll adapt it down later this week. Also, the red vacum line where the tee goes is smaller than 1/8'. Had to do some widening of the red vacum line to get it barely onto the variable tee (minimum 1/8" ) I had. I would also recommend 1" hose clamps for installing the valve switch. 7/8" would only engage the about 2-3 threads and one stripped out the first thread which I had to replaced with a 1" and was much easier.
Elder User
Joined: Sep 2004
Posts: 780
Likes: 1
From: Chicago suburbs
I did the air conditioner/heater core bypass mod today. Well almost anyway. I downloaded some instructions awhile back calling out 3/16" vacum line from the vacum tee to the valve switch. Actually I used 3/16" fuel line. However the valve switch plug is smaller. I think it might be a 1/8" so I'll adapt it down later this week. Also, the red vacum line where the tee goes is smaller than 1/8'. Had to do some widening of the red vacum line to get it barely onto the variable tee (minimum 1/8" ) I had. I would also recommend 1" hose clamps for installing the valve switch. 7/8" would only engage the about 2-3 threads and one stripped out the first thread which I had to replaced with a 1" and was much easier.
Read this link here to see some pictures and an added mod to this mod.
Dave..
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Tuned
Joined: Aug 2003
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I thinik the white line only engages the valve when you use MAX AC. But the red line engages the valve whenever VENT, AC, or MAX AC is used. I decided I liked this option better.
Elder User
Joined: Jun 2005
Posts: 567
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From: Albemarle, NC
i originally tapped the red line too. i thought "cool, cold air with just the vent." well the first somewhat warm day this year, the girlfriend informed me (you know what i mean) that i needed to fix that. it was too cold, and i couldn't adjust the temperature. so now i have it in the white line, and it works perfectly. if i have it on max a/c, even with the fan on the lowest settings, it is still almost too cold. that's the shizzle. i had an old '83 s-10 blazer that the a/c was messed up on. only two settings, wide *** open or off. it would actually freeze over the vents if i closed them off.
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Tuned
Joined: Aug 2003
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I have heard about the no adjust/too cold problem. But I was thinking that was due to a complete shutoff to the heater core. I tested the bypass switch I used (AutoZone #74809) before installaion and noticed it still had about 10% flow thru in the bypass mode. I also wanted to see how well it worked in the normal AC and vent modes. Its hard to imagine any AC being "to cold" in Texas during July -September.
Before this mod my vent gauge said the duct temp is only about 5 deg cooler in MAX AC mode than in Normal. Does anyone know what the difference is between MAX and Normal AC modes. I'm thinking that they just reduce the cycle time on the AC compressor.
Before this mod my vent gauge said the duct temp is only about 5 deg cooler in MAX AC mode than in Normal. Does anyone know what the difference is between MAX and Normal AC modes. I'm thinking that they just reduce the cycle time on the AC compressor.
Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
It's just the source of the air to be cooled through the evaporator coil. MAX gets it from the already-somewhat-cooled cabin air, NORMAL takes the hotter outside air.
Some manufacturers call MAX "RECIRCULATE", instead.
Pop
Some manufacturers call MAX "RECIRCULATE", instead.
Pop
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Tuned
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From: Monroe VA
Been having some vacuum problems and had to unhook mine to be sure that wasnt my problem. Didnt realize how much of a difference it made til it was gone. I wasnt real happy with how cool the vent was so when I put it back its going in the white line, cause thats where that **** STAYS this time of year anyway.
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