Hi
The lights of my car are slightly weak when the engine is idling but when I rev it up, they become stronger. Is the alternator going bad? It is a 66 Ford Mustang 289 with 39k miles.
Hi
The lights of my car are slightly weak when the engine is idling but when I rev it up, they become stronger. Is the alternator going bad? It is a 66 Ford Mustang 289 with 39k miles.
Get a multimeter, set it to volts DC and see what is says. It should read 14.7 volts at maximum.
Do you have any aftermarket stereo systems? When it's dark, and I'm driving my 1979 Catalina, I'll notice the headlights dim just a tiny bit when it idles. The car has an aftermarket stereo and it sucks more power out of the battery.
@justin-shepherd No. I've put a performance ignition coil.
Is the alternator going bad?
You should be seeing between 13.5 and 14.5 volts the battery, and no more than 14.7 as noted by @justin-shepherd. If you have the original type mechanical voltage regulator that may need adjustment if voltage is out of specification.
