Well, here is what I know now. I took the van back to the dealer and said, "How about humoring me and having an HVAC tech check my system?" After telling me again it was normal for the system to cycle the compressor while in manual mode, he said ok, we'll look at it. The result of that was that the tech reported he ran all the diagnostics; there were no codes and the system was running normally. The service writer enjoyed telling me that. I thanked him and left.
Because this had only started happening recently, I decided to dig into it a bit more with the assumption that the system was really in auto mode, not manual even though the "auto" icon was not showing. Here's what I found: the owners guide says that the auto mode "offers a full range of manual override capability for each function". ie. the user can switch from the systems chosen fan speed or vent distribution while other aspects of the system remain in auto mode. AND, if you change any one setting the "auto" icon on the display will disappear. So, what's hidden in this explanation that they don't really explain is that the absence of the "auto" icon doesn't necessarily mean that you're in manual mode. It could mean that you're just not in full auto mode ie. you've chosen your own fan speed, for example. In the meantime, the compressor is cycling because it assumes you still want the remaining auto functions. Not a bad assumption necessarily, it's just that the icon ( or lack of it ) is no longer a reliable indicator. They should just leave it on or change it in some way if they feel they just have to remind you that you've ignored the systems choice of fan speed or whatever.
Now for the interesting part: the owner's guide doesn't mention how to switch the system to full manual which would mean the compressor won't cycle unless you turn on the defrost or manually select the air conditioning. By fiddling around I found a way: From within auto mode ( the icon is on or even if it's off if you've changed the fan speed for example,) MANUALLY select the air conditioning ( even if the compressor is already cycling ). This causes a "snowflake" icon to appear on the display. Now, manually press the air button again. Presto, the snowflake disappears and the system goes into full manual with no more compressor cycling until you call for it by selecting defrost, air conditioning or ( I think I'll just never do this again ) selecting "auto" .
I'm convinced that sometime in the last 6 or 8 weeks we got it in auto mode then we ( and by "we", I mean "my wife") changed a fan speed or vent setting causing the "auto" icon to disappear. Then when we recently made a trip to Deleware from Ohio I thought it was in manual, but kept hearing the compressor cycling. That's when I started digging into this.
I've run through this several times now and it works that way every time. The owners guide certainly doesn't make it clear and the dealership people don't know it or don't wan't to be bothered to explain it. One of my buddies asked me if I was going back and tell the service writer about this. No way do I need the aggravation. His eyes would glaze over. It's just too easy to keep saying, "that's completely normal." Anyway, if I'd just been clairavoyant enought to devine what the service manual writer hid deep between the lines, I would have missed this challenging puzzle.
In spite of my general dislike for the auto mode, I do like the automated temperature control ( which continues to function in manual mode ) and it's split driver/passenger temp settings. I also am aware that you can get the split temps in a fully manual system. Probably would be the best for me and just change the heat/cool setting as I need.
Sorry about the long post. I didn't have time to write a shorter one.
