Two or three times a year when I have turned off the pickup with the A/C running... the next time you get in to start it up the A/C does not work, control panel for the unit is completely blank.  The first time it happened I swore it was because someone messed with my settings, but now it has happened on several more occasions. 

Usually about the third time you start it after this happens it will go back to where it was & work fine. Sometimes it takes a few days.   On one occasion it started back up while we were driving down the road.  When I took it in to the dealer they told me they had no way to know what caused it if it was working when they looked at it. Not surprisingly my dealership has since gone out of business, so I'd like to not look like a total idiot when I take it to a new dealer for service & ask them to fix it.  It's been my general experience that I have better luck with repairs when I tell them what is wrong before they open the hood!  Thanks in advance for any help you have.