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I am trying to find out if a 1974 corvette should have a heater control valve when equipped with AC. Some parts catalogs show it as stock, but some sources indicate that heater control valves were not from factory. I purchased a heater control valve before tearing into my car and I am starting to think my car did not come with one from the factory. I am not seeing any mounting holes for it and no indication of an available vacuum line. I am hoping those of you with a 74 with AC and try and see if you have one.
Heater Control Valve from Corvette Central/Paragon:
Where it may be mounted under the outer heater box:
The NCRS tech manual (the newest), is invaluable for these sort of things. I've attached the page for the water-shut-off valve...you've got the right part and correct location. You can see that it was a mid-production add for cars with A/C and eventually became basic equipment.
Many thanks. It looks like it was added to 74 mid year, which is why some people seem to have it and others not. I am thinking my car was not originally equipped with it.
Many thanks. It looks like it was added to 74 mid year, which is why some people seem to have it and others not. I am thinking my car was not originally equipped with it.
Also realize the benefit of adding it now that you have it. Apparently, the engineers realized, after the fact, it was helpful.
It's interesting to see the various posts on this topic when we look at AIMs, parts catalog, etc. That is why when we revise an NCRS manual, we look for cars deemed to be of an original configuration, study and draw some conclusion about what rolled out the factory door. Also know, and many of you do, that AIMs are snapshots of time. Those pages were changed in and out throughout the production year...a copy was not absolute. It's the aftermarket that sells a "version" of the original and it may or may not be complete, representing the final product.
You will need the vacuum switch mounted on top of the heater box, activated by swinging the heat control lever to cold and the door all the way closed. A quick look behind the map pocket will tell you if it's their. If not you can add it as well. Turning off the hot water is a very good thing indeed.
1974 Heater Control Valve?
