ORIGINAL: Katzmans Caddy

jrm347, in case you are not sure how to get the codes you can read them yourself form the DIC, dash panel in other words. My Deville is newer than yours but in mine with the motor running or accessory keyed you press the off and heat buttons simultaneously until the panel lights up and the codes begin to show. During this process it will pan through all of the various codes and show the history. Have a pen and paper ready to write them down, things like U1255 or P0300, whatever. I'll give you a web site to go and look them up. After all of this the computer will start to go to each code type and ask you if you want to look at them again, press the fan increase speed button, after this it will ask you to Clear Codes?, press the fan increase speed button to clear them. If there are codes in there and this clear codes process does not put the light out your buddy may be telling it like it is. If you clear them all and the light comes on again you are going to have to address the problem, but at least you will know what to look at because the likelihood of numerous codes will be diminished. As it is now you may have a lot of history. One other thing, codes will be marked History or Current (usually stays Current for a few hours when a problem occurs then is religated to History). To reset the DIC turn off the key or as in mine hit the air recirculation button

http://myweb.accessus.net/~090/cadidiag.html

This web has the codes and other information.