Rd 688 External Vent ?'s

[therabbittree]

I'm working on a 1996 Rd688 if you move the heat control lever to any setting the outside air vent opens. Is this normal? Seems like you would want it closed for heat? and want it closed for A/C recirculate in the summer.

Thanks,

Deo

[oldmacktrucks]

I would assume you have the Red Dot heat/ac box in the truck with the air slider controls. I know that if the selector is on max a/c or off the cowl vent should be closed. Vent, defrost, normal a/c its open...not sure about heat.

[Lmackattack]

You want a little out side air to enter in the cold winter months because your body heat lets of moisture. When you have the windows rolled up the out side air will help take up that moisture and reduce the windows from fogging up. just like defrosting the windshield... you want out side air to take the fog off the inside of the glass. If your red dot unit is hooked up properly it will automaticly operate the cowl vent. max ac the vent is closed. you should be able to adjust the door to limit how much it opens to let out side air in.

[therabbittree]

Thanks!