All electrical lights will dim high and low while running

derekhay316

Registered User
Only when the car is running all lights in the car (headlights, dash, radio...) will dim from normal intensity to a darker intensity over and over again relatively fast. This will last for a couple minutes and then go normal for a couple minutes and then back again. It does not do this when the engine is NOT running though. Any idea what i should do with this? Should i just take it to ford or what? i'm lost. My only guess is the alternator.
 
Last edited:
derekhay316 said:
It does not do this when the engine is running though. .


then its not the alternator, because your alternator only runs when the car is running, and it powers the battery so if it only does it when the car is off, id say get a new battery
 
Well your post is a bit confusing, I think you wanted to say that it doesn't do it when it's NOT running, right?

I had the same issue, it was the alternator.
 
Sounds like the alternator. You should be able to check the output by hooking up a VOM to the +/- terminals of the battery (engine running, lights and anything else you normally have powered on).
 
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