AC/Heater control

[JohnsRed79]

I just had my AC fixed, but when ever I switch it to AC it only blows air out by my feet. What steps do I need to take to check how to get it to deflect to the other outlets. Also what would make the fan stop on its own . Ive replaced the relay.

 

[Bob Chadwick]

Had the same problem on mine. Replaced the control head and everything works fine.

On the 77, you have vacuum coming into the control head. When you move the vent/defroster/heater/ac slider it ports the vacuum out to different places controlling the flow of air. I didn't have to play with mine so I'm not 100% sure on this but I think the vacuum goes to an actuator on the left side of the distribution stack behind the instruments. I would check for vacuum coming in and see if you get it to come out of different lines as you play with the slider. If that happens, there is a good chance that the actuator is the problem.

The first step for me would be to identify the vacuum line coming into the head unit and make sure vacuum is present. If not, then go back toward the engine. If you have it, go the other way.

Check out this information, which includes a vacuum diagam.

If you have no fan at all I would start with the fuse.

Good luck.

Bob