Headlight relays are circuits that help provide power to your headlight system. If your headlights are not working, you may have a faulty relay. Removing a relay is simple once you locate it. The Ford Focus has several headlight relays; each powers a specific headlight beam.
Determine which relay you need to remove or replace. Your Focus uses four relays (two for high-beam and low-beam, two for each side). Turn on your headlights and determine which one is faulty.
Locate the correct headlight relay. The headlight relays are in your engine bay fuse box. Relay 16 powers your driver's side low-beam; relay 26 powers your driver's side high-beam. Relay 17 powers your passenger side low-beam; relay 27 powers your passenger side high-beam. Remove the plastic fuse box cover and use the numbered diagram to locate the relay.
Remove the headlight relay. Grasp it firmly and pull straight up to remove it. To replace the relay, or install a new one, push it straight down until it "snaps" into place. Replace the plastic cover when you are finished.
If you determine the relay isn't the problem, try replacing the headlight bulb; if that doesn't help, you may have a wiring problem. Wear gloves when removing a relay, for extra grip.
Shut the engine off before removing a relay or working under your bonnet.