Looking for pictures or a description/diagram of 68' 300 NON-a/c heater box?

sprice

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I rebuilt this box probably three years ago and just got the mechanical s under the hood working. Had a problem with the heater control connection but have since replaced with a good one and tested with a NOS part. Both are responding the same. Issue is on OFF, both actuators close. On DEF, both actuators extend, and I get good air out the left defrost outlet, not the right side. Pushing the HEAT, the left actuator pulls in but little to no air in the floor vents. When I removed the heater control from the parts car, I believe I replaced the vacuum hoses on my car with the same configuration that was assembled on the parts car but not 100%. The hoses and actuators tested good with a manual vacuum pump. I have tried switching the hoses on the center actuator with no change. There are 7 vacuum pins coming off the heater control. This reduces to 5 vacuum lines a few inches along. Two with white stripe, two with red stripe and one vacuum source line. I am hoping its a vacuum hose issue and not something I may have missed upon reassembly. As I recall, there wasn't much to screw up inside the box however I still have success in that department at times.
 

Ross Wooldridge

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It sounds like things are mis-plumbed with the vacuum lines. Do you have the factory service manual? It should show the routing.
I believe Red stripes all go on the same sides of the vacuum motors, and the white stripes on the other. Open and Close - might help solve the issues.
 

sprice

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Ok, only thing I could find in the FSM was on page 1-8. If I missed something, let me know. Looking at the illustration it seems the center valve shuts the air on and off, which could be why it only moves with heat/max heat//def or off. The drivers side actuator deflects air to the defrost or floor. Kind of makes sense. I'll give it a try. Thanks for the tips.
 
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