the condensor on the back of the alternator is used to filter out radio frequency (rf). rf is generated anytime there is a spark, it is a very small signal but large enough to render your radio usless. a quick test is to start the car, turn you radio on a.m. and listen, if you can hear it without alot of noise overrunning the station it is ok. note, most radios including our beckers incorporate "filter" circuitry in them. thus, the condensor keeps your noise out of the guys radio next to you at a stop light.

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matt