Hello,

There is not supposed to be a relay for the headlights.

All of the power for the headlights comes from the headlight switch which then goes directly to the foot dipper switch.

The power from the headlight switch goes to the center connection of the headlight switch.

Using a test light, check for power at the center wire of the dipper switch when you turn on the headlights.

If no power then check the wires on the back of the headlight switch.

If you have power check the connections at the dipper switch.

If you have the original switch, the wires are retained by set screws which can come loose, so you may have to tighten the set screws.

If that does not fix the problem, try using the foot dipper switch several times to see if the switch has a problem.

And then check the headlight bulbs themselves.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502