I installed a Lariat cluster a couple of months ago, and like yours, my A/C
didn't work, because of the different way the XLT and the Lariat
communicates to the PCM for A/C request. I talked to one dealership and they told me that it couldn't be reprogrammed. So I wired in a couple of relays so my A/C would work when you turn the control to A/C or defrost.
My question is, the "as built data" that was loaded to your cluster, did they
have to "tweek" the numbers or was it a direct "as built" load? I talked to a tech., and that was his question. He's willing to reprogram and I'm going in next week to have it done.