The Headlamp Relay is part of the car electrics system. We have 3 associated problem symptoms connected to it.
The headlights don't always switch on after pressing the headlights on the button or stalk in the car. Occasionally the headlights will go off and need switching on and off a few times to get them back on again.
The headlights won't switch on at all after pressing the button / turning the stalk. The rear lights and indicators appear to work ok but the headlights are not functioning at all.
The headlights don't seem to be as bright as they were, they don't light up as much of the road ahead as they used to.