buzzing sound?

OK
strange one on my 1990 XJ

Just started, and it does not do it all the time! I started to hear a buzzing sound, kinda like a seat belt buzzer, but softer. So here is the strange part, it goes away when I turn ON the headlights or parking lights!

I know the car has a buzzer for when you leave the lights on, and you turn off the key, but this happens when I drive, and when I pull the knob on the headlights, it goes away!

Any thoughts on what this might be????

Thanks in advance,
RG

follow the sound.

on my 89 there is a white plug in module on the left side of the fuse block for the seat belts.