Ac/heater install question

[matt030305]

Hello all, I have a 1970 Duster with original ac and heater.

It has the original ac heater box with all the other actuators and vacuum lines.

But the previous owner took out the ac compressor and disconnected everything involving both heater and wiring. I have been able to rewire the climate control unit but I cannot hook up the vacuum harness properly. I have looked in the manual to see if I can find a vacuum hose diagram but I haven’t found anything.

NOTE: I’m only trying to hook up the heater and defogger in time for the winter (don’t have a compressor for it yet)

Could anybody tell me what vacuum hoses have to be connected in the engine bay in order to get the actuators to work properly when switching from “heat” to “defog”

Let me know if you need any pictures.

Thanks!

 

[dd70340]

Do you have the Factory Service Manual? If not you can download it here Service Manuals – MyMopar. In Group 24, Air Conditioning, the Evaporator Heater Assembly section has the hose diagrams for the heater and defroster.

 

[67Dart273]

OP may be right, I don't find it in the 70 Plymouth manual, nor the 70 Dart/ Challenger manual.

 

[matt030305]

The best I could find are these photos, but they do no serve any sort of information on how the harness is connected and where the vacuum source is.

 

[str12-340]

vacuum source is a small tube from a big plug in the in the runner on the passenger's side in back of the carb. If you have power brakes you should have a large and small vacuum fitting in the same place. Far right side of picture below

 

[Demonic]

There's only one hose to the engine source. If any are not connected under the dash, they have to be plugged, as it could be a small vacuum leak. Easy.

 

[Charrlie_S]

The AC/Heater control vacuum diagram is in section 24 page 55 of the 1970 plymouth service manual. Manual can be downloaded from mymopar.com

 

[townsend]

Did you notice that pages 24 - 52 thru 24 - 61 are in the Barracuda section?

 

[BillGrissom]

If I recall the factory AC in my 1969 Dart with the pneumo-electric 5-button pushbutton switch, there are 3 vacuum hoses to the engine bay. One is the vacuum source at the intake manifold, usually shared with the big tube to the brake booster, a spider-tube fitting. The other two hoses go to the water-valve (push-pull vacuum operation), which shuts off water flow to the heater core when using AC. The defroster door would be controlled by a vacuum pod under the dash. Most/all are also push-pull so 2 vacuum tubes. There are color stripes to distinguish the hoses (recall green and red). You can still buy the 5-button push-button switches new (~$90).

My 1965 Dart is factory non-AC and has manual climate cables. My 1965 Newport is worse since factory non-AC but a 4-button pneumo-electric pushbutton "not avail". Long ago, I hacked a way to substitute a 5-button switch. I also added a relay for Blower-Hi position so that high current doesn't melt the pushbutton and blower switches, often a problem as-found in many cars by many manufacturers before they learned to embrace relays.