oscillating Lights

[slayer_of_fords]

My lights are oscillating... It only happens when it is under 30 ish degrees. It gets really bad at idle when cold, to the point that all the lights in and on the truck are almost blinking on and off. This is all lights/screens/headlights/tail lights. The speed at which the lights oscillate is dependent on how many rpms the motor is running at. You can also hear a whine like noise that is synced to the dimming and brightening. It is a 2004, 4.0 165k is miles.

Thanks for reading

 

[JoshMcMadMac]

Sounds like a dying battery, or less likely alternator.

 

[slayer_of_fords]

If the battery was bad, wouldn't It have trouble starting the car? This first started when i changed the alternator. And you can hear it make that noise synced with the pulsating lights. It sounds like a whine or squealing. Thanks

 

[JoshMcMadMac]

If the battery was bad, wouldn't It have trouble starting the car? This first started when i changed the alternator. And you can hear it make that noise synced with the pulsating lights. It sounds like a whine or squealing. Thanks

If it started with a new alternator and it is making noise, then yes that is the more probable culprit. Drop the serpentine belt, start it up, and see if the issue is resolved. It would also help if you have a multi-meter to check the voltage at the battery.

 

[slayer_of_fords]

Here is a video i took of the problem.. I just can't get my head around why it only does it when it is below 30ish degrees.. I am going to try and replace the alt. Are there any brands that are better than others? Where do i find what amperage the current alternator is?

http://www.youtube.com/watch?v=BjYDA1Wp_Kg

Thanks again

 

[blueoval9erlifer]

Does the alt make noise when your lights are not on the STROBE setting? Or does it make noise all the time? if it only happens when its cold out might want to check connections maybe you got one thats not completely tight and when it gets cold out it contracts enough to cause that?????

My buddy says not to by remanufactured alts your getting what you pay for spend the extra and buy a new one.

 

[slayer_of_fords]

I can hear it when it is not cold out a little bit. It is much louder while really cold. the colder it gets the worse it does it. I will go out and check the connections and maybe throw some dielectric grease on there for good measure. Thanks for the suggestion.

 

[blueoval9erlifer]

no problem let us know what you find. its been a long time ago and i wasnt very old but it seems like we had that kind of problem on an old tractor and the voltage regulator was going bad. but i coud be mistaken. If you just got the alt. i would go exchange it for a different one under warranty. And check all the connections while swapping it out.

 

[slayer_of_fords]

I was thinking about a voltage regulator actually. Does anyone know if these alts have one or if it might be on the truck somewhere?

 

[JoshMcMadMac]

I was thinking about a voltage regulator actually. Does anyone know if these alts have one or if it might be on the truck somewhere?

Voltage regulator is internal to the alternator. Remove the serpentine belt and see if that resolves the issue.

 

[corkey]

my 99 did this once last summer when i washed everything under the hood,
the alternator got wet , and once it dried out , it stopped,

it is a sign something is not right for sure, my guess might be the brushes starting to go bad, and that is what is causing the surges of power,