The headlights don't work on the scooter; I

The new headlights, probably blew the fuse check the fuse and relay if so get a bigger fuse to run the new headlights. Remember when replacing any light in your vehicle to not touch the glass part of the bulb with your bare fingers..

yes ,
check the fuses.

If Halogen light bulb:
Ok then this is either an issue with the headlight switch or harness to the headlights . We're these checked ?

Don't know the vehicle but I would check relay if fitted then the switch

Hi Joe

I don't own a Ducati or know it's circuits.
But, as an ex auto electrician I suggest the following.... if your short of electrical tools.

Use a simple wire from Battery 12v terminal (with a fuse or 10Amp circuit breaker in series with the wire.
Connect to headlight connector low beam / high beam to see if it works.
Lights work OK?

Use a simple 12v test light connected to ground or Battery Negative to trace the wire back.
Check on either side of connectors.
Check Fuse Block with test light to find open fuse.
Process of elimination

Good Luck

Hi Harlan.

I see that you mentioned a 1999 Dodge Grand Caravan in your other question. I assume this question is about the same vehicle.

The checkup will start from the fuse and relay in the power distribution center. A way to test the relays is swapping two relays of the same kind to check if that makes any difference.
If relay and fuse are OK check the wiring to power distribution center, check the dimmer switch and the connection to BCM (the module under the dash).

I have uploaded relay map and wiring diagram at this link. Please click on the link. If necessary click on the picture again to enlarge.

Regards.

The DRL's are separate from the actual headlights. It sounds like your headlights aren't working at all. The first thing I would check would be the headlight fuse(s), or relay(s). The location for these should be in your owner's manual.

Hope this helps!