I have a 300 2008 my key start not l working sometimes not unlocking the doors or the trunk work off and on I thought maybe battery going bad yesterday started car went to store went to leave put key in it turn car wouldn't crank took key to auto zone change battery still key not connettig to ignition car battery is good maybe key have a short

Try jump start. Lights on may have drained battery enough due to bad connections to cause this.

No mention of make/model but does key fob open doors OK? If so it isn't the fob batteries... Could still be a bad button on the fob but it could be a balky solenoid on the trunk latch. Maybe try 12V direct to the solenoid?

Sounds like the body control module is going bad. Need to be sure, not cheap.

if the key turns in the cylinder then the door panel needs to come of and check the lock rods if key does not turn cylinder then the cylinder was changed at one time and there is another key for the door. see if the key works in other locks on car

have you tried replacing the batteries on the remote?

The fob itself is bad. You can sometimes take them apart and clean the contacts but 9 times out of 10 they have to be replaced.

This is the key security system. Somehow youv'e set it off. Used the wrong key tried to open the door with the alarm on. Opened the door or trunk from the inside after locking it from the outside. If your the real owner of the car it'll be no problem to get it fixed. If you have the correct key lock the doors from the outside with the key and lock it twice ( the doors ( all of them ) should lock). Leave the car alone for a minute, maybe 5. Then unlock the door twice, all the doors should unlock the second time. Enter the car and start it with the key. If you with a remote door lock fob that can work too. If this fails then try a different door or even the trunk. Sometimes the driver doorlock switch wears out or gets ice in it and unlocking a different door or useing the remote can get you going again.

You might just need to reset it. Roll the drivers window down and close all the doors. Lock all the doors with the key ) turn the key to lock twice, The electric locks should lock all the doors. wail a few minutes and unlock and open the trunk with the key. relock the truck or just close it. unlock the drivers door with the key, twice. all the doors should unlock, get in and start the car. Now this does'nt always work. If it does'nt we'll make the system think it's running. Close and lock all the doors. open the hood and disconnect the battery, one ccable will be fine. wait a few minutes. Reach in though the open window and turn the key all the way on. Don't open the doors, go around and connect the battery hard so it does'nt jump or skip. Reach thought the window and start the car/ once it's running. turn it off remove the key and unlock the door from the inside and open the door ( as if you were inside.) get in and start the car and everything should be back to normal.

you may have to replace the remotes and then have them reprogramed for the car because they do go bad but if there is an autozone near you they will test the remotes for free

I locked the 2000 lincoln continental with the key fob but lost it now the ignition key wilolo not unlock the door