What could be the problem with my autolocks? They will unlock with the remote but not lock? Help?

Question

I have a 2004 Toyota Corolla

Answer 1

check the ground off your module, you should also have a fuse associated with the ground wire maker certain you are getting continuity through that fuse.

Also check the connection to you lock wire. I have seen  many times where installers use t-tabs and over time vibration causes a bad connection.

Other than that t would be inside your lock module itself, being the fact that vehicle is a type b door lock system , which calls for a direct hook up.

Answer 2

try new battery in remote

Answer 3

I have seen bad door switches cause this problem on Honda's.  I'm sure your Toyota uses similar inputs.  If the vehicle thinks the door is open it wont let you lock the door (  keeps you from locking your keys inside ).   Doors will still unlock. Possible bad door switch.