Surging lights man

[soulcrushing71]

Well I have just defeated my charging system demons, and everything is working well. Problem is it seems that my lights kind of surge and pulse with the engine. Also my alternator light used to come on very brightly before the charging system was figured out, now it glows very dimmly. Shouldnt it be off totally.

[soulcrushing71]

A friend told me I have a bad ground somewhere, where is a good place to start looking and is it possible to be in my dash?

[fordman]

the grounds would be in several places. i will just make a list

battery to engine.
enigne to firewall behind drivers valve cover
core support to regulator and alternator.
behind the instrument cluster on the dash support
on the front of the core support behind both headlights.
if you have a 70-72 behind the tail lights for the side marker light.
those are goignt o be the major ones. and a minor one too. and they make be more that run here and there through these other grounds. but those are the first places to check.

[Thunderfoot]

That problem is usually related to the Voltage Regulator or the Alternator... The VR is what controls the "Alt" light on the dash as it (the VR) is the ground point (electronically) for the Alt light. The VR is also what controls the Alternator output and if it is not controlling it steady then the lights will surge with the voltage change... Faulty alternator will also cause a "Steady pulse or surge" in the lights when one or more of the diodes in the alternator die, it will still put out voltage just not a clean DC voltage.
In your case it could be either the Alternator or the Voltage regulator. even if you just put NEW ones in (been lots of people getting bad "new" ones). I would take and have your alternator checked at the parts store and if it checks out fine would replace the Voltage Regulator.

[soulcrushing71]

Thanks for the info guys.

[BigBlueF250]

My old 68 Mustang had the surge also. New regulator cured it as well.