Pulsating interior lights?

I come to notice that all my interior lights on our 2000 Montana are constantly pulsing. When I rev up the engine, the pulsing doesn't change and at times I
believe that the pulsing stops. The headlights are very consistent during all this testing. Any suggestions on a possible solution? Thanks
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TWRud wrote:

Let me take a wild guess at this one. The alternator has three sets of rectifiers (diodes), and normally all three sets are working, and the electrical output to the rest of the system is relatively smooth after being filtered by the main battery. If you blow one set of rectifiers, then it all works pretty good, but you might see some pulsing on the 12 volt bus. The actual voltage (13-14 volts) may appear rather normal, or it may droop a bit, especially under load. If you blow out two sets of rectifiers, then you get the same symptoms, only much worse. At that point, you probably are not getting much of any charge into the battery, so you may end up with a "no start" condition.
Go have your alternator tested, and tell them what you are looking for when they already have the tester on the system. You can't judge much about the viability of an auto electrical system without some meters.
---Bob Gross---
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On 04 Aug 2003 20:54:02 GMT, snipped-for-privacy@cs.com (Robertwgross) wrote:

I second Mr Gross's hunch on this one. You can check system voltage with a DVM set on "AC volts" with engine running & a load on the alternator. An oscilloscope is even better. Anything more than 0.1 volts AC is trouble.
Regards, Al.
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Al wrote:

Yes, the part of the problem is the mindset of the troubleshooter. If you think of the auto as having a purely DC electrical system, then you are missing part of it. The power is actually generated as AC and then rectified down and smoothed. 95% of auto electrical testing can be DC-only, but you really want to drop an AC meter across it to see that ripple is as low as it should be. If ripple is high, then you have either blown rectifiers or else a bad battery or else very bad wiring.
---Bob Gross---
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Check your post in the pontiac group I posted a bulletin there
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