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View Full Version : Symptoms of a failing alternator?



JD525IA
06-06-2006, 05:34 AM
Driving in this fine a.m., I noticed that all my dash lighting were sort of pulsating. It was not a lot, but I could definately tell that the level of the lighting on the dash and the console/radio was getting slightly brighter and dimmer at a rate of two cycles per second.

I haven't had any problems starting or anything, but could this be a sign of my alternator getting ready to crap out, or possibly the diode going?

The battery is 1.5 yrs. old and it has been 110 deg. F this week, so I know it is hard on the battery. I'll check the battery water level.

Opinions?

JD

Tiger
06-06-2006, 06:04 AM
Measure voltage at idle. You can also take it to Autozone for free charging system test.

tnt525i
06-06-2006, 07:14 AM
if you have the on board computet, you can do a test #9 and check the voltage, 13.6 to 14.6 is within range,,,, anything lower you may need a new voltage reg or alternator
hope this helps

BobHarris
06-06-2006, 09:45 AM
My 93 518 did this. It turned out to be the regulator / rectifier unit (little black box on back of alternator). This was a replaceable unit on mine.

HTH

Bob