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 Post subject: Intermittent flickering of lights
PostPosted: Tue Dec 08, 2015 9:17 am 
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I'm experiencing some intermittent flickering of the lights (interior and headlights) as of late. The problem seems to be a bit worse just after startup at idle, but even after a full run cycle, there's still a flickering dimming action going on. It seems to correspond to minor surges in engine RPM, but I don't know if the engine RPM is causing the surges (It shouldn't) or the surges are being caused by intermittent misbehavior of the alternator. BTW, no problems starting or with any other electronics.

Has anyone had something like this? I'm thinking the voltage regulator function in the alternator, but I'm not sure how to troubleshoot it.

Dan

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 Post subject: Re: Intermittent flickering of lights
PostPosted: Wed Dec 09, 2015 10:50 pm 
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Alternator is probably dieing then. Whats the voltage of the battery before and after engine start?

Put an intense elecrical load on the jeep. Maybe a 600w inverter connected directly to the battery. If the lights flicker or stay dim for a good amount of time id start looking at AC Delco alternators. Also, the belt could be slipping on the alternator pully.

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 Post subject: Re: Intermittent flickering of lights
PostPosted: Fri Dec 11, 2015 9:04 am 
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PALiftedKK wrote:
Alternator is probably dieing then. Whats the voltage of the battery before and after engine start?

Put an intense elecrical load on the jeep. Maybe a 600w inverter connected directly to the battery. If the lights flicker or stay dim for a good amount of time id start looking at AC Delco alternators. Also, the belt could be slipping on the alternator pully.


Good thoughts. I had the alternator tested (with lights, AC, etc.) and it didn't even blink (unlike the lights which were flickering the whole time). The clutch was replaced with a new litens unit about 6 months ago. I'm VERY familiar with what the failing clutch symptoms are. Also, the "no other electrical problems" part leads me to think I may have a grounding problem.

If I remember correctly, the higher-amperage loads are fed from the panel up by the battery and anything below 30A is from the fuse panel by the steering column. Is anyone familiar with how all the grounds are run?

Dan

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 Post subject: Re: Intermittent flickering of lights
PostPosted: Fri Dec 18, 2015 3:13 pm 
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So, here's my results with the voltmeter:

14.3-14.6 VDC (varrying) - Vehicle running with lights (flickering)

- remove voltage regulator plug from alternator assembly

11.9 VDC - vehicle idling with lights (no flicker)
12.1 VDC - vehicle idling, no lights
12.4 VDC - vehicle off

So, I assume this indicates I have either a bad component on the alternator (is it serviceable? I don't want another chinese rebuild like this one is...) or on the BCM since that's where the voltage regulation logic is on the 2005 CRD.

Thanks.
Dan

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