1998 honda civic ex driver side door will not lock?

the answer depends on what you mean by "will not unlock". there are three different conditions where it won't unlock

1) the door will not unlock with the key

2) the door will not unlock with the remote

3) the door will not open with the inside lock button

4) the door will not open from the outside or the inside

when it will not unlock with the key typically it is because of a damged lock cylinder. a lock cylinder would have to be replaced or rekeyed by a locksmith to fix this.

when it will not unlock with the remote or from the switch on the driver's door the the issue is a bad door lock actuator inside the door

it usually runs about $150 to replace the door lock actuator. this assumes the passenger door opens with the remote. if the passenger door does not open with the remote as well then check the battery in the remote control

if the door will open with the key but not open from the inside the problem is with the linkage on the door lock inside the car between the lock button and the lock. it usually runs about $50 to fix the lock linkage

when the door will not open from outside or inside it is because the door latch is seized.. this is an expensive repair as the interior has to be removed to get inside the door. expect about $300 to fix this condition

don't know which condition you have.

hope this helps

Can you be more specific?

Will it not lock with the keyless entry system? If thats the case, the actuator could be dead.

If you are trying to lock the door from the inside when you are getting out of the car, then you need to pull the inside door handle and push the door lock.