We have 2 very ****ty Chevy Astro vans at work. Any ways, the heater only works out of the defrost no matter what selection you have it on.

What could cause this and how can I fix it?

Thanks,

Jake

 

what year? sounds like a resitor pack, or the vacuum lines in the switch are boogerd up.

 

astro van heaters are the worst the vac lines rot like crazy on em things almost every one i work on has a bad vac line somewhere.. any way check the vac lines on the left side of the engine bay... ones next to the blower motor... find the bad one and change it out then your heater will work like it should.. also check the vac ball its below em things mounted on the inner fender they like to crack as well

 

Thanks guys. Sucks being cold.

 

my ranger was doing this a bit ago. on our rangers (and at least my year) the blend door and (I'm just gonna call it this) duct door are run off of separate vacuum lines in the dash. My vacuum leak turned out to be my PVH solenoid assembly up by my bumper, but that leak was enough to default my duct work to defrost but still worked my blend door. I could get some air to the floor, only if I rvv'd the engine up a bit.