What does this mean? (Video enclosed)

[pjoll84]

Hey everyone,

I noticed my gauge cluster gets brighter as I rev… like a moped and it’s headlight with a magneto system… what could cause this in a vehicle?

Video enclosed
Interior lights brighten

 

[R413]

Normal.

Look in your service manual electrical section. To do charging system retests it uses 1200 RPM in many instances. It doesn't fully charge at idle speed. They made millions of cars like this and they made it through the warranty period and decades after. Not a problem. It's better on 1970 and newer Chrysler car with dual field alternator and electronic voltage regulator.

 

[Lefty71]

My '64 is exactly like this.....but only to a degree.... as described above..once you are well above idle they are bright, and do not continue to brighten further.

 

[w.Hudson]

To help that situation make sure that you idle speed isn't too low.

Also an alternator with a small pulley will help by increasing the alternator speed at idle.

Often a failed alternator will be replaced with an alternator with a pulley that will work on many different models and is a
larger diameter.

 

[davek]

Its a mopar

 

[pjoll84]

Thanks everyone! Only used to a magneto doing the bright thing but glad everything is all in order and this is normal. Idle is set for 750rpm, alternator does not look original

 

[Geoff 2]

Check the alt voltage, should not be more than 14v.

 

[451Mopar]

Common with stock alternators that don't output much power at idle.