ticking sound at idle increases in frequency when the headlights on

[rtiburon]

It's not really loud but you can definitely hear it at idle. Turning on the headlights or the rear defroster make the ticking speed up but I can't see the rpm change. Has anyone heard of a ticking alternator issue?

I suppose it might be valves but where would the electrical relate to that?

Any suggestions are much appreciated.

 

[RonJ]

You need to pinpoint the source of the noise.