Heater core hose setup

SvtLdr said:
Sounds like you may have an electrical problem? You should be able to turn the fan completely off.
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I've never actually checked if the fan was still blowing or if it was just air being forced through from driving down the road, but I assumed because there is no "Off" labeled on the control panel that it was just the lowest speed. It has 4 dots on the fan control, from small to large. Guess it will be easy enough to check.
For sure I will be putting some kind of heater core bypass on it this summer though. Not sure why I hadn't thought of that before.
 
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DaYooperTransplant said:
I have a 97 with no A/C, and even if I have both levers from the control panel all the way to the left, heat still escapes into the cab from the vents. I wonder if this was someway to bypass the heater core so you didn’t get that. If it is, I’d be interested in the parts used. It can get miserably hot in the summer while driving. There’s actually no “off” on the fan control so it’s always blowing a little.
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Not sure on specific years but I've noticed that the fan won't shut completely down until you move the mode knob to off.
 
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DaYooperTransplant said:
I've never actually checked if the fan was still blowing or if it was just air being forced through from driving down the road, but I assumed because there is no "Off" labeled on the control panel that it was just the lowest speed. It has 4 dots on the fan control, from small to large. Guess it will be easy enough to check.
For sure I will be putting some kind of heater core bypass on it this summer though. Not sure why I hadn't thought of that before.
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The top slider, all the way to the left side is OFF. It should be labeled "O".
 
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That is definitely a heater control valve. Sometimes they call it the Max AC Mod. The vacuum hose attaches to the recirculation actuator. So shuts off flow to heater core, but not the engine. Ford installed the same setup in the Super Duty Trucks. Since I live in Louisiana so I am going to add one to my Jeep. You can use Motorcraft YG350 heater valve for a Ford Ranger, a section of vacuum hose, some hose clamps and a vacuum tee to connect to the recirculate actuator. My truck ac gets way cooler.
 
DaYooperTransplant said:
I have a 97 with no A/C, and even if I have both levers from the control panel all the way to the left, heat still escapes into the cab from the vents. I wonder if this was someway to bypass the heater core so you didn’t get that. If it is, I’d be interested in the parts used. It can get miserably hot in the summer while driving. There’s actually no “off” on the fan control so it’s always blowing a little.
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When the HVAC system is working correctly no heat from the heater core escapes into the passenger compartment and the fact hot coolant flows continually through the heater core is a non-issue. There is very likely a vacuum leak in the HVAC's control system so it's not closing the flapper door all the way.
 
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I have seen where people rig up something similar on Rams to remove any heat from the HVAC box to increase AC's effectiveness . I never felt if was worth it but most who go through the trouble won't admit it didn't do much I'm sure. I see their logic but cannot see it doing a whole hell of a lot even if you are removing 210 degrees only divided by thin plastic
 
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