what could this be?
when driving everything is fine and the A/c blows ice cold. but if i'm stopped in traffic suddenly the heat will overpower the air conditioning? is this monovalve relatated? i've already replaced it three times, although the build quality is a joke...do they really fail after like three weeks? or could it be something else? this is with the temp wheel clicked on MAX

__________________
1981 NA 300D 310k miles