I have been trying to hook up driving lights to an 1999 Honda Accord EX.
Previously when doing this I have controlled the driving light relay by a line running from the highbeam headlight to the relay and then to ground.
Now when I do this the driving lights remain on continuously. This made me think that the ground side of the headlights was being switched.
I have tried multiple possibilities of this simple wiring job and cannot get the results that I want. i.e. the driving lights come on and off with the highbeams.

Verify that when you hook 12 volts to coil, it makes and breaks relay contacts.
With the coil to ground and the plus coming from headlight, when headlight switched off, the relay should open, lights go out.
One of 2 problems exist, the hot from headlight switch is constant hot, not highbeam hot.
Or contacts on relay welded, or stuck shut. Be sure to fuse power from battery to relay contact.