And I have to give all the credit to F150online.com, as this is where I had found out that my problems were VERY common for 04-08 F150's. This is also where I found out their was a TSB (tech service bulletin #8-23-6) explaining how to fix the problem.

It was a temperature regulation issue (cycled from freezing, to cooking, with no possible in between setting) and it was due to a bad actuator.

It was kind of funny, as their was 1 female in the parts dept, who knew what I was talking about, and agreed that the TSB mentioned here probably did apply.

.....while the actual service manager acted like, "Well.... I dunno.... we'll see......"

At the very least, when all was said and done, he did admit that the TSB# I gave him, did in fact apply, and that it was the actuator.

In any case, I procrastinated on having this fixed for SOOO freaking long ! 2 1/2 years ! Doh ! And it works so well now.... WTH was I waiting for ?

Oh well,
Much thanks again.
Fish

PS, Now, I find myself reaching up to adjust the temp every few minutes.... and then I'm like, "Wait a minute.... this temp is fine" ! LOL