Replaced MFD did not fix problem

I've had a bizarre situation where I cannot turn off my air conditioning, changing the temperature causes the vent configuration to change, I cannot display trip information from the steering wheel etc. What happens is that if I touch one of the vent buttons or the AC button, it greys out for a moment then returns to its prior setting. I cannot manually change vents; if I change the temperature settings, the vent selections change by themselves.

I thought this looked like a bad MFD, so I purchased a new one and installed it. Unfortunately, all the same problems exist plus I now have a large triangle with an ! In it.

If the problem was not a bad MFD, what could be causing all of this?

Forgot to mention that this is a 2005 Prius

Followup: I ran the engine for awhile and the Warning triangle disappeared as did the symbol indicating a bad HV Battery Pack. I'm now back to a squirrely MFD display that won't allow me to turn off AC and the steering wheel button for Info that doesn't work.

 

Replaced the battery a few months ago.

 

UPDATE: Given that the weird behavior of my MFD did not change when the MFD was replaced, I decided it was time to take it to the dealer for a diagnostic. As a reminder, here's what was going on:

• AC stuck on. tapping the button caused it to grey out for a few seconds then return in the ON state.
• Changing temperature (via steering wheel or touch screen) caused the vent selection to change
• I could change fan speed with no issues.
• I could invoke the INFO display ONLY from the MFD, not the steering wheel.
• Other than temperature changes, I could not select a different vent setting successfully: button would grey the return to old setting.

Well, the dealer service technician came out and saw the problem. He then starting tapping buttons all over the place: defrost, Auto, Off, vents, AC, etc.. over and over again. All of a sudden, everything started working correctly! He had no idea why nor did I.

I drove out hoping it would stay this way.

If anyone has a clue what might have gone wrong, I'm still interested since I have no idea whether this fix is permanent. I'm also wondering if I should take the time and trouble to remove the new MFD so I can return it for a refund. I'm inclined not to mess with success!

 

Yes, battery remained connected. Everything came up ok except warning triangle which disappeared after awhile. The malfunctioning ac and vents continued as before the MFD swap.

Only the wild button pressing by the tech cleared the issue! I dont know which manual page describes that procedure. <G>