You asked for advice, so I will give you my .02cents worth :)
For what it's worth, I have read your other posts concerning you and your husband's issues...so here it goes:
To me, you seem to be a tad bit difficult to communicate with and what (maybe) is happening is that your husband is having the same problem? I mean he says it to you in the first line of his IM...'Your not gonna be difficult with me'? This to me, is a blazing red flag but not in your favor, in his b/c he sounds like he really is having a hard time and to him you are being difficult. I only say that after reading all your other posts and by how you perceive your conversations going back and forth...and how you explain them to us.
My advice is along the same lines as one of the other posters have said, maybe try saying less, not more. I know you wish to solve your communication issues but less really might work in your favor?
I also agree that IM'ing or texting is NOT the way or the place to try to have an adult conversation and unlike some of the other ladies on here, after reading your IM exchange I did NOT see a controlling husband, I saw a husband who is FED UP with having to deal with trying to 'explain' every little thought to his wife. I mean (and I am sorry when I say this) but how hard is 'turn OFF the AC' to understand? And then wanting to communicate how you just didn't get it over and over was exhausting just reading it, let alone being on the other end of it...ya know what I mean?
I really am trying to help. I am sorry you and your husband are not "seeing eye to eye" as you like to say and hopefully you guys can get on the same page soon. From the outside looking in, it sounds to me like your husband is getting fed up with you and all your 'reasons' for wanting/needing to do things your way....again, sorry that sounds harsh, I am just giving you my opinion from reading all your posts about this.
Please don't hate me. If you do not like what I have to say you are free to disregard all that I have said.
But if I were you, and I loved my husband and wanted our marriage to work, I would take a deep breath, a big step backwards and start looking within and how what I am saying/doing is not helping and what I can/should be doing differently to start bridging the gap between us.
~You were 100% wrong BTW when you were telling him in the IM/text for him to try to make sure what he says makes sense? Right after he says 'No Promises' you go on about him needing to make sure what he asks of you to make sense? He made 100% sense when he asked you to turn OFF the AC...you were the one in the wrong when you didn't understand that you had to push the lever/switch on the unit on the wall. Then by you going on and on about it was wrong, you should have just said right away (while on the phone & then he could have told you to go to the wall unit) that you didn't get what he was saying and then admitted you were wrong and that you finally figured it out. And then instead of bringing it up the way you did in the IM/Text you should have led with the fact that you were in the wrong. Not to mention that in the line where you are trying to tell him that 'typing might not be the best medium' you sound all sorts of controlling and trying to be 'right' when you are trying to place blame on him again for making 'statements that could be misconstrued' by you? All that is instigation and trying to pick a fight, IMHO.
Please again, take what you like and ditch the rest. Just trying to give an outsiders unbiased opinion on what you have given us!
((Hugs))