Help needed. '94 with heating problems

I have a '94 convertible (LT1)that been giving me little to no heat. Both hoses going into the firewall were hot and I am getting SOME heat.

Today, I think I stumbled upon a possible cause and I'm hoping that someone who's been there/done that has the cure.

I had to change out the Surge tank/overflow hose & pipes today due to a leak. In the process of bleeding out the system and taking it out for a shake down run I noticed something peculiar. Even though I'd cranked the heat all the way up to 90 degrees after the engine warmed up, as usual I received very little heat at the floor level. The REALLY strange thing was the A/C never cut out. The pipes were collecting moisture (even though it was set to put out maximum heat and ambient temperature was < 82 degrees)and the system pipes that are normally supposed to be cold when the A/C is running were as cold as the proverbial witch's left ***. It seems the A/C never shuts down.

To further test my theory I turned the automatic climate system OFF and drove about 30 miles in 62 degree weather with the interior temp set to

90 degrees. While I could feel very little warm air coming in (since the system was off) I DID feel some heat. I pulled into a lot and lifted the hood to check the A/C components. All were at ambient under hood temperature as you'd expect.

Shut the hood and took off, turning the climate control back ON for the remaining 10 mile run to the house. As soon as I turned the system ON the heat literally gushed out at the floor level and it was really putting it out. As I continued to drive, however, the output cooled down and the "heated air" was, at best, merely tepid. When I arrived back home I again popped the hood and found the aforementioned cold parts very frosty again. The damn A/C is tempering the hot air output.

No, the defroster was not on - I realize that that will cycle the A/C. I tried it with the lower vents selected as well as the Automatic mode and it really didn't seem to make much difference. The output definitely cooled down once the A/C got going. Seems like I'm taking all that nice hot air and forcing it through the A/C unit or vice versa.

Question is: How is the A/C controlled in this system. Is there a relay that is supposed to take it off line? Is it the control head that's FUBAR? I had been thinking I had a door stuck in the heater or something. Apparently that's not the case since I have a good air flow coming through down there.

A/C works fine, it just seems that it's working way too much and should be taking a seat on the bench when I'm calling for a cabin temperature above the ambient temperature.

Any help or advice would be very much appreciated.

Thanks

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Unquestionably Confused
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