Will 85 heater control work in 81 K5

[TC70C10]

Are these two interchangeable. The 81 had add-on air installed at the dealer when new. Controller had a/c, heat and defrost. Phantom dually has one from a 85 with a/c, vent, bi-level etc.

Has anyone swapped these out? I don't care if everything works, but would like a/c, heat and defrost.

Thanks

[old Rusty C10]

pull yours out if they look the same they will work ( i never had dealer installed air but im sure its the same setup)

[78SilveradoSWB]

I believe there was a change in the heater/AC controls in the 1983. I had sold one recently from an 85 and when I did some research on it, it fits only 83-87 models. I was going to use it on my 78, but realized it used vacumn lines versus linkage and the lens was shorter. In catalogs, they go from 74-80, 81-82, 83-87 which tells me there are difference between years. Hope this helps you.

[TC70C10]

Thanks Mitch, That's why I posted the question. I noticed in LMC that they show 81-82 and 83-87 and they don't list one for A/C in the 81-82 models. Dealer said the 81 - 82's have been discontinued.