Automatic Climate Control

Fresh/Recirculating Air Switch "OFF":

Image Reference;
S24 Fresh/recirculating air switch
Y34 Switchover valve unit 4 connections:
1 Switchover valve for legroom laps
2 Switchover valve for defroster flaps
(short stroke) and center air flap
3 Switchover valve for defroster flaps
(long stroke)
4 Switchover valve for main air flaps
35 Vacuum connection on intake manifold
36 Check valve
37 Vacuum supply tank
38 Vacuum element for defroster flaps (flaps "closed")
39 Vacuum element for legroom flaps (flaps "closed")
40a Vacuum element for center outlet flap (flap "open")
42 Vacuum element for main air flap left (flap "open")
43 Vacuum element for main air flap right (flap "open")

Fresh/Recirculating Air Switch "ON":

Image Reference;
S24 Fresh/recirculating air switch
Y34 Switchover valve unit 4 connections:
1 Switchover valve for legroom laps
2 Switchover valve for defroster flaps
(short stroke) and center air flap
3 Switchover valve for defroster flaps
(long stroke)
4 Switchover valve for main air flaps
35 Vacuum connection on intake manifold
36 Check valve
37 Vacuum supply tank
38 Vacuum element for defroster flaps (flaps "closed")
39 Vacuum element for legroom flaps (flaps "closed")
40a Vacuum element for center outlet flap (flap "open")
42 Vacuum element for main air flap left (flap "closed" with 80% recirculated air)
43 Vacuum element for main air flap right (flap "closed" with 80% recirculated air)


Color code of vacuum lines:
bi = blue
ge = yellow
gn = green
gr = grey
rt = red
ws = white
hbl = light blue
drt = dark red