Noise from dash cluster
 

I've owned my 2003 Splash Green Miata over three years now and for about the last two and a half I've had a noise coming from the dash cluster. It started with a sound like electrical arcing from idle to around 2K. When the electrical load was changed it would stop. Explanation being if during daylight hours when heard turning on the lights made it stop, if night time when heard turning lights off it would stop. The alternator was rebuilt by a reputable company a few months back replacing brushes, bearings, regulator and rectifier. The noise now has changed to a clicking sound, like a relay opening and closing and stops when electrical load changes just like before. Has anyone experienced this or knows how to correct it.

Well, if they charged you for a regulator I wouldn't call them reputable any longer. NB alternators don't have regulators. That function is handled by the ECU.

And if they switched to an internally regulated alternator that may be the problem.

My understanding is that some regulating of output voltage is inside the alternator. Prior to having it rebuilt, when checking voltage with VOA meter readings of 10 volts noted at idle to 15.7 volts around 4K. After rebuild readings of around 14.5 volts noted through RPM range.