Key wont come out ignition and won't start?

SOURCE: key stuck in the ignition and wont let me out of gear

The shank of any GM key hits a lever that locks the key in place when turned into any position other than the off position. If it stuch in off, the cylinder must be replaced

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: Starting disabled remove key

VEHICLE ANTI THEFT SYSTEM HAVING PROBLEMS

SOURCE: cadillac seville won't start

I've got an even cheaper and easier solution, instead of buying a new cylinder, find that plug and snip the orange wires going to the old cylinder.Then remove the resistor chip from the key and solder each of the the wires to each side. this will fool the car into thinking the correct resistor chip is in place, allowing you to use the original key or any copies with or without resistor chips. i just did this to my caddy and it roared to life! :)