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Flickering lights making me sick!


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I have noticed a problem develop over the last year or so and it has unfortunately been getting worse. At night when I turn on my interior lights they have a flicker or pulsation. Its in my map lights, glove box light, the light that lights my spedo and tach, and I think also my headlights and fog lamps. Its just getting worse and I would like to try to figure it out but I dont even know where to start. Any thoughts? Im going to be very upset if its my alternator of battery again. :P

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Hi, my neighbour's Oldsmobile just had that exact same problem.

It was the Alternator.

Just a little tidbit for you.

Barry

2008 STS V8
2016 Colorado Z71
1970 Corvette LT-1 Coupe

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Its the alternator as Barry noted. If you have a digital charging meter on your car look at it or hook up a volt meter on the battery and you will see the voltage varying wildly. Your alternator probably needs brushes or a regulator. My 91 did the same thing. Mike

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Like a couple of the others said, it’s definitely the alternator. (A year like that?? How many miles were run in that condition? Just curious) Anyway, what almost always goes on these alternators is the rectifiers (diode bridge). The quickest way to be certain is go to the voltage readout on your display (if you have one) or read the charging voltage with a VOM. If the voltage is holding over 14 volts, it’s the regulator. If it’s fluctuating between 11-14 volts it s the diodes. The brushes a rarely a problem. They outlast most everything, and typically just need a little cleaning. The diodes are about 90 bucks from RockAuto. Or go with a AC Delco remanufactored for about 175. (No new ones available for early years anymore,but AC Dleco reman is still your best choice for reliability.)

'93 STS.. opened, dropped, wide...fast.

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That diagnosis is good to know Bob thanks. If he is fluctuating a new Diode bridge would do it..

The diode bridge can be tested by using an ohm meter, if power flows only in one direction shes a good, if it flows in both directions she Kaput.. There are typically three diodes and they need to be tested individually.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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All this solid state PFM is a passing fad. We need to steer the power generating folks back to a big, heavy, inefficient 14" to 16" long generator that use the good old reliable commutator and brushes for rectification.

It was good enough for Thomas Edison!! :D

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Hrrm does this make the 3rd or 4th time the alternator will need to be replaced in the last few years? Who can keep track of such things. I had a (heavy duty) 200 amp alternator made for my stereo. Its been nothing but trouble and I dont have my ghetto blasters back there anymore so I think its time to go with another AC Delco. Bastages! : )

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I got a chance to talk to a friend of mine today, he works with the electrical systems on new GM cars at Milford proving grounds. He seems to think that I should check my grounds first. He suggested starting with the "chassis ground" I think it was. Is that the one on the left side of the engine by the belt? How do I check it? Check for a voltage drop?

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