I have a remote keyless entry system. When I press the button on the keypad, the interior and cab lights come on like they should, but the locks do not unlock. I also cannot use the lock/unlock buttons inside of the truck, as they will not work either. I already checked the fuse under the hood in the power distribution box, but this fuse is good. Is there a relay somewhere or something that could be causing this???? This is a 98 f-150 4x4 by the way.

 

anyone have any ideas?

 

First thought would be the harness. Check the harness on the inside of the passenger side kick panel then the drivers side. Then check inside the doors. I believe there are two relays for the doors, one for each side. So both of them going out at the same time is unlikely. They should be behind the passenger kick panel as well. Also, I know you said you checked the power block under the hood but there are also relays blocks under there as well. Mine is an '02 so I am not sure just how similar it is to a 98.