I have an 1980 with an issue that I am looking for some help on.
This vehicle was in North Carolina and not driven for the last 2 years. When I got it her to Ohio, temps were still cool and I switched the temp control to warm. All functioned as it should. Problem is now it wont turn back to cool. The lever slides fine, and the selector diverts air where it should, just always warm.
Any suggestions of where to start?
Thanks in advance for your input.
Chris

 

Well, what you need to understand is that there are several sources of warm air getting into the passenger compartment. Obviously, the heater is one of those sources. The vacuum-operated hot-water "cut-off" valve is supposed to prevent hot water getting to the heater core, unless the control is set to "Heat". So, that valve may not be working properly...or the vacuum signal may not be properly sent. Then, the various vacuum-activated servo doors on the heat/A/C ductwork might not be working properly, and [in your case] not closing off the heater outlet. Again, the servo man not be operating the door correctly or the vacuum signal may not be sent...or received...properly.

Lastly, there are a few sources for 'extraneous' heat getting into the cockpit: the kickpanel door(s) might not be sealing well nor opening/closing properly; the rear hood seal (if your year uses one) may be worn to the point that it no longer seals, thus allowing engine comparment heat to get fed directly into the cockpit air inlet (cowl area of right fender); and the all-too-familiar condition of exhaust pipe heat coming up into the passenger area from directly below.

To get a good handle on unwanted heat, you need to check out the heater control head to make sure it is working as intended and that activation switches mounted to it are doing their job. Also, the vacuum distribution manifold (mounted to the left side of the control unit) has good integrity...not broken and sealing well...and the vacuum lines are sending proper signals and those servos receiving the signals act appropriately.

There are lots of things that need to be checked out and actions that need to be taken to assure that unwanted heat does not get into the passenger area. Good luck on checking out your car's systems and successfully resolving your heating issues.

 

My issue appears related to the heating side rather than heat from exhaust or engine. I can change the selector to defrost and at least direct the heat up but then the blower also blows. When the selector is in the off position and ignition turned on I hear a motor type noise from the area around the heater core. May have to go with the dreaded mechanic, I just hate to pay for them to learn.
Thanks again

 

The temp door is cable operated on your 1980. Check to make sure the cable isn't broken and is actually moving the door.

 

I do not see a cable, only a vacuum operated device under the hood.

 

Take the left side carpet panel off next to the console.

You will see a cable coming from the temp control slide. It operates a door to select hot or cold or a mix.

 

Thanks Ill take a look. Is the door behind the glovebox or below?

 

Thanks Max, that was the problem. The holder came loose. Thanks again.