Heat only controls (what cable does what?)

[sventinker]

In my 70 no a/c c10 my father in law added the factory style a/c heat controls and none of the cables line up with the new control. So I want to learn what the cables do so I can figure out how to rig it for heat and or defrost this winter. Would a heat only truck have 2 or three cables? would it have a shut off valve in the line feeding the heater core? Is my stock fan motor 1 speed? or does it vary based on resistors? The fan control I have now has multiple positions.

I know its a lot of questions but I don't know anyone with one of these trucks I hope you guys can help thanks.

['68OrangeSunshine]

I believe the Standard Heater Control had 3 cables.
DEF

FAN

HEATER

[LockDoc]

Originally Posted by sventinker

In my 70 no a/c c10 my father in law added the factory style a/c heat controls and none of the cables line up with the new control. So I want to learn what the cables do so I can figure out how to rig it for heat and or defrost this winter. Would a heat only truck have 2 or three cables? would it have a shut off valve in the line feeding the heater core? Is my stock fan motor 1 speed? or does it vary based on resistors? The fan control I have now has multiple positions.

I know its a lot of questions but I don't know anyone with one of these trucks I hope you guys can help thanks.

3 cables. No valves in the lines. A diverter door controls whether air goes through the heater core or not.

Here are a couple of pictures. The top cable on the control goes to the front control arm, the middle one goes behind the heater box and to the bottom, and the bottom one goes around the heater box and into the heater box by the firewall.

The third picture is the blower motor resistor. It's located on top of the interior heater box on the right side. They can be pretty fragile so use a small screwdriver to gently pry the connector off if the terminals. I think the blower motor is basically a single speed motor and the resistor controls the low and medium speeds. High is a direct 12 volts. The switch is on the side of the heater control panel and the middle lever controls it. You can see the switch in the first picture where the connector is.

LockDoc

[sventinker]

Ok thanks, So the control I have is for an a/c truck. I Don't know why he added that as he never spoke of putting a/c in this truck. Looks like the cables go in all different on the a/c control versus the heat only and the electrical plug is different as well. Thanks again for the information

[LockDoc]

Originally Posted by sventinker

Ok thanks, So the control I have is for an a/c truck. I Don't know why he added that as he never spoke of putting a/c in this truck. Looks like the cables go in all different on the a/c control versus the heat only and the electrical plug is different as well. Thanks again for the information

No problem. Any more questions let us know....

LockDoc

[LukeandI]

Why not just swap out the ac control to a non ac control? They are a dime a dozen. OK... not quite :-)

[sventinker]

So I went to hook up the motor so I could get some heat in the cab regardless of where it comes out and the motor was bad. $20 later and the motor is replaced Just got to love how inexpensive some of our parts are. I figured what wire was what and made my own harness to the stock plug I have all three speeds now.

So that brings me to this issue and I know you guys might say to pull the air box but in this picture I can see where one of the cables are supposed to go but is there a plate missing? what goes in this hole? And I assume this is the flap that will circulate air through the heater core? Anyway a lot of air comes out of this hole and when I cover it more air comes out of the floor vent. When I divert to the window defrost without and ducts installed yet very little air comes out of those holes.