Got no Heat Blowing out of the inside vents with the controller in the Heat Hi or Lo Position . Checked the Heater Control Valve on the Firewall and it is not receiving a Vacuum signal in any position. I tested this vacuum motor and it seems to be working fine. I wired this vacuum arm open but I stll have no Heat inside the car. The cable for the Heat Control is working correctly at the heater box. This is a 1972 Mav 302 with AC - AC is working OK. Any Ideas ? I`m Freezin !
There are many vac lines inbthe system try this link as a starting point http://mmb.maverick.to/attachment.php?attachmentid=24350&d=1197138517
Feel for you Tim! The blower motor in my '72 decided to take a crap on me the other day, so I have been driving without heat in this cold ass weather too.. I gotta run to NC in the morning and grab another blow motor off one of my other cars. I would start by Checking all the vacuum hoses. If you don't hear any hissing or any obvious signs of a vacuum leak, maybe a hose could be pinched somewhere or something.
Make sure one of your hoses isn't crimped up under the dash.Put a core in my 73 Grabber back in high school and got a hose mashed up in there.COLD air!
I finally have heat ! - thought I would post just in case someone else ran into the same problem. The heater control valve that mounts on the firewall has 2 vacuum hoses . I had checked the one on the top and it was good , However the one on the bottom had hardened at the connection and was split causing the vacuum motor not to function. I cut off about 1/2" of hose to get back to more flexible hose and reconnected. That one little connection shut down my entire heating system. All is good and warm now. thanks for all the suggestions.
