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Discussion Starter #1
Was backing into the driveway last night, applied brake and noticed the light reflecting off the garage door was pulsing. Got out and noticed all the marker lights are pulsing/dimming... Going from normal to dim and back. I haven't tested anything yet but perhaps someone has had this issue and can lend some advice. I just did an alternator a few months ago and hoping it's not defective (was annoying to install).

Thanks guys

~Brad
 

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Discussion Starter #2
Apparently it is intermittent... Was doing it earlier today, just started the car cold and it isn't doing it anymore. Battery is 11.90V off, car on 14.20V so that seems about right... I wonder if once it warms up there is a short or something somewhere... Or if my BCM (or LCM?) isn't properly regulating the voltage?

Any advice/insight would be greatly appreciate. I'm going to wait for it to happen again and check to see if the volatage is in flux at the battery. I guess that would probably mean the alternators voltage reg is going?

Thanks again :)
 

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Usually the LCM when this starts to happen. The LCM controls the pulse width to the bulbs, they're not just on, but on 90% of the time, and when the LCM starts to go, you get a flicker. But I would agree, make sure no ripple from the alternator.
 

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Discussion Starter #4
Usually the LCM when this starts to happen. The LCM controls the pulse width to the bulbs, they're not just on, but on 90% of the time, and when the LCM starts to go, you get a flicker. But I would agree, make sure no ripple from the alternator.
It was doing it again this morning, but not a few minutes ago on the drive home... I need to pickup an analog meter to know for sure... My digital one was flipping between 14.22-14.30, doesn't seem like enough pulsing to cause dimming... Then again the refresh rate on the digital might not have a fast enough refresh. Since it keeps happening intermittently I'm going to check all the grounds also and make sure the hot wire on the alternator is secure... You'd imagine if the voltage regulator at the alt were failing it wouldn't be an intermittent problem.

as always, thanks for your posts! :)
 

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Discussion Starter #5
Little update... Grabbed an analog meter, I don't see the alternator pulsing beyond +-.10... If it were the voltage reg at the alt you'd imagine the interior lights pulse too right and the meter would be jumping a little more than it is? The interior lights all seem stable despite the exteriors pulsing.
 

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Discussion Starter #6
I'm at a loss with this... Volts at the battery seem between 13.8-14.20... I pulled some ground wires, wire-wheel cleaning, refit. The issue is completely intermittent. Nothing else in the car pulses other than the exterior lights. You'd imagine a bad voltage regulator on the alt the interior lights would pulse too right? Engine off no pulsing. Regardless the next time it warms up enough outside I'll be investigating more connections with a meter trying to trace this unless someone has any advice/suggestions.
 
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