At the beginning of the problem the blower moter ran continuously I ran the OBD using the climate control buttons, I came up with two codes. Can't remember them now. (After reading the other posts I suspect the BCM) About a week later the fuel data center and climate control only show lower case c's in their displays. I can't get into OBD to check.
During this time I got a no charge lite, I replaced the Alternator, charge problem went away but not the c's. I autopsied the alternator and found the diode and brushes bad.
Not sure if the problems are related.
The car runs fine, no fan of course.

My guess is that it is the BCM went bad. Have that computer checked out before you spend the $$$ on a new one just to be sure. Good luck.

What is the BCM? I have this problem now with "c" on fuel and climate and the blower wont shutoff and i got SES light also

I see the same problem on an 89 deville I was lookin to buy.
What is the cure??

Has anyone replaced the BCM yet.

If memory serves, theres a thread about it in the FWD Deville section (its a bit older though) The BCM did solve the problem. The "C" is the display panels way of indicating it has lost the clock signal, which boils down to a fault in data transfer from the BCM. Typically, a BCM internal fault is the cause of this.

You too?! I'm glad I'm not alone in this. Do you have heat? Mine just blows cold air constantly! Very occasionally mine will read "d" only to be replaced by "c" shortly after.

That's exactly my problem too!
Think i need to replace the BCM?

My brother just called with a similar problem, said the info center was only showing 'd's. he's not that savvy when it comes to cars so getting any more specific with him could be difficult. any cure?