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'98 Accord EX lights dimming

Whenever the alternator of my '98 Accord sedan gets an additional load put on it, the headlights of the car temporarily dim to some degree. This additional loading seems to take place whenever I turn on the rear window defogger, A/C, or fan. The alternator belt isn't very old at all and it isn't loose either, so I am suspecting that the alternator itself could be on its last leg.

Other than the alternator belt or alternator itself mentioned above, is there anything else that could be causing this dimming of the headlights whenever HVAC controls are turned on?

Thanks in advance for any help/advice that you may have to offer me on this one.

Ron M.

Reply to
Ron M.
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if you're talking about with the motor at idle, it's normal. all cars do it. look at the power output of an alternator vs. rpm's.

Reply to
jim beam

My recollection is this is perfectly normal. With the headlights on and the car cruising, adding further load (like defogger, A/C, interior fan) will lower the voltage at the alternator's regulator, and so dim the lights.

For reinforcement of this, see the service manual page for testing 1995-97 Civic's charging system, at the link below. Note that the voltage "checks sat" if, with the engine running and the headlights on, and then the interior fan and defogger is added, it drops from over about 13.6 V to under

13 V.

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"Ron M." wrote

Reply to
Elle

"Ron M." wrote in news:sLdGf.19382$% snipped-for-privacy@tornado.southeast.rr.com:

Some dimming at idle is normal, as jim says.

If there's excessive dimming until you rev it, it's a battery thing, not an alternator thing. Make sure the battery measures 12.65V with the engine off.

Possibly the Electrical Load Detector going bad?

Reply to
TeGGeR®

Thanks for all of the responses. Based upon the responses that I received to my original post, I probably shouldn't be too concerned about this issue since the dimming effect is minimal and for an extremely short time duration. The reason I inquired about this issue is because no other vehicle that I have owned since 1977 has ever exhibited this same type of behavior. Not a single one. I purchased this car used on Dec. 28th, 2005 and really do like it a lot so far. This slight, temporary dimming of the headlights has pretty much been my only concern with this used car to date.

Once again, I appreciate the info!

Best regards,

Ron M.

Reply to
Ron M.

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