Heater blower

[1970Dart340Swinger]

Anyone have a hint here? (65 A body Dart)
The heater blower works fine at all speeds when A/C or Max A/C is selected but does not work in Heat or Def positions. There is power to the vacuum switch at C1 and C1A as indicated in the diagram. No power to C4A. I replaced the A/C and heater vacuum switch but still the same. I can't locate the blower motor resistor or the resistor bypass switch to check connections. Dart manual not much help.

 

[65 Dartman]

The blower motor resistor is on top of the heater as is the the resistor bypass switch. I just took these pics as both units are out of the car being rebuilt with the DMT kit. The wiring diagram is right out of the factory 65 AC service manual. I suspect you might not have the correct heater/vacuum switch as the connections are very specific and don’t correspond to later switches - JMO

 

[1970Dart340Swinger]

The blower motor resistor is on top of the heater as is the the resistor bypass switch. I just took these pics as both units are out of the car being rebuilt with the DMT kit. The wiring diagram is right out of the factory 65 AC service manual. I suspect you might not have the correct heater/vacuum switch as the connections are very specific and don’t correspond to later switches - JMO

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[1970Dart340Swinger]

Thank you very much for this -- very helpful.
When I first got this car the heater blower worked fine, but I replaced the vacuum switch because the OFF button was jammed. The heater blower didn't work with the new switch so I reinstalled the old switch and heater blower still doesn't work, so I don't think the new switch is the problem. I have been poking around under the dash fixing various problems and I'm wondering if maybe I knocked a connection off somewhere. Now that I know where these components are I think I can reach up under there and feel if everything is connected.
Thank You for this help.

 

[1970Dart340Swinger]

Thank you very much for this -- very helpful.
When I first got this car the heater blower worked fine, but I replaced the vacuum switch because the OFF button was jammed. The heater blower didn't work with the new switch so I reinstalled the old switch and heater blower still doesn't work, so I don't think the new switch is the problem. I have been poking around under the dash fixing various problems and I'm wondering if maybe I knocked a connection off somewhere. Now that I know where these components are I think I can reach up under there and feel if everything is connected.
Thank You for this help.

 

[1970Dart340Swinger]

Just to follow up, I see that the bypass switch is mechanically operated. I won't know until I can get to the car tomorrow, but I have a real clue as to the problem. Some where in it's life, the underhood A/C components were removed, but the underdash parts are there. There is a metal bracket that restricted one of the doors from moving that I have not reinstalled because it didn't make sense to me. I have a feeling that if I reinstall that bracket the heater blower will come back to life.
I'll post a reply tomorrow
Thanks again