I have a 1998 lesus ls400, when i turn off the car and remove the key, the engine shuts off however the dash lights, headlights stay on and the steering wheel does not return to the off position. I disconnected the battery then reconnected and everything worked as it should for about 20 seconds, then returned to not working. the electrical system thinks that the car is still running.

SOURCE: with the ignition off, the rear tail lights won't turn off

hiya if the rear lights are remaining on ? with no ignition it will be the brake lights staying on this is easily remendied/ checked by trypulling the brake pedal up by hand and see if lights go off ? if so then you will need to adjust the b/light switch which is positioned adjacent to pedal and can be screwed inwards towards the pedal untill the plunger on switch is pushed into the switch which puts lights off ensure pedal is fully up then adjust switch reconnect the wire/plug and press pedal slightly to ensure b/lights operate ok and then go off with pedal released ? on hyundai the brakelights do not req ignition on to operate hence more likely problem is as above good luck

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: 99 chevy cavalier theft system light on steady, car wont crank.

My 2000 cavalier has done this for 6 months. You take your key out then open your door, wait ten minutes and the system resets itself and the car will start-annoying you bet!!!