After i changed the ignition switch in my 1983 cadillac now the horn wont stop blowing

SOURCE: 1994 Cadillac DeVille wont start sometimes

Bad contacts in the ignition lock cylinder.

SOURCE: 1997 cadillac concourde deville, car wont start

Try to reset the p.c. by unpluging the batt. for 10 min that should do the trick.

SOURCE: 88 cadillac deville, ac blower fan wont shut off,

Ralph,
Most common cause of this is the blower fan (proper name for the fan you refer to) continuing to run is a shorted out Electronic Climate Control Module. This solid state device replaces the older style fan speed resistor block (at about 4 times the price) This unit is found on the top of the HVAC box under the hood. (HVAC means heating, ventilation and air conditioning) The HVAC box is found on the passenger side of the firewall. Look behind the A/C's accumulator. It will have an electrical wiring plug on top of it. It will be fastened to the HVAC box with a few 7mm hex head screws. Very easy to change.
FYI, do yourself a favor and replace the blower fan motor at the same time. The Electronic Climate Control Module usually fails because the motor is drawing to many amps of current. This is because it's bushings are worn out or the brushes are worn out.
This is very common on Cadillacs and Buicks.
Charlie
PS Not sure why car won't start. Either you drained the battery or blew a fuse which controls starting the engine. Need more info regarding the "no start" condition.

SOURCE: cadillac 2004 cts, wont start

i had a 2003 ctc that did the same thing, it wouldn't start or would make a clicking sound and about 1 mth after the problem started aND mechanics could not find a problem my car caught on fire and burned completely from something under the right side of the hood. i had just parked the car and got out, it happened really fast. the fire chief said the cause was unknown????

now i have a 2004 cts and i'm having the same problem!!!!!!!!!!!!!!! has anyone else had this happen???? please be cautious if your cts is doing this, during the fire my doors locked and had to be pried into by fire chief.

SOURCE: My 1990 Cadillac Deville wont start or engage starter

hey there. my name is dwayne, and im contacting you for help on my 98 caddy deville. well three days ago. i got a alarm installed. and friday i was driving on da high way and it just turned off. and smoke started coming from my steering wheel. engines coolant temp. was only 200 no smoke was coming from engine. now car wont start at all.!! please help