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Using accessories, like hazard/flashers, causes other lights to dim, or wipers to slow. At idle, hazards cause a faint whining sound, WAAA-aaa-WAAA-aaa-WAAA-aaa, lower pitch when the hazards are lit. Also, sometimes the car doesn't want to crank. It randomly won't want to crank on the first try, like it has a bad battery the dashboard lights dim, second try key on it cranks just fine and starts right up.

Using a multimeter while running, alternator seems to produce 15.2V-16.5 volts. While off, battery has between 13.6V and 14.2V. If I run the headlights for two minutes, then crank, voltage drops to 11V while cranking, then bounces right back up to 13.6-14.2V.

Seems like the alternator and battery are OK, but there is some other weird problem going on.

Bad ground or a short somewhere? Bad voltage regulator? Bad ignition switch or starter solenoid?

A few months ago the car would randomly lose power and shut off and occasionally the ABS self-activated, momentarily jamming on the brakes.
 

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Yikes. That alternator is putting out way too much juice. I predict a bulging battery in your future if you continue to run this way.

Your battery seems healthy based on the voltage drop you are showing while cranking.

I'd check all your grounds to solve the dimming/slow cranking, then replace the voltage regulator to bring that charging voltage back into the normal range. 14.5 V max.
 

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To add to that, unless you have an oscilloscope handy, have the alternator tested at a parts store.
That little hand-held thing, among other things, will check the integrity of the rectifier bridge in the alternator. One symptom of a failed diode is (can be) higher than normal voltage. Also, the AC voltage will play havoc with the car.

It'd be a shame to replace the regulator, only to find that the alternator has a bad diode....

Starting issues:
Inspect both battery cables. Better is doing a voltage-drop test on them (which is a lot simpler than it sounds), to verify that they're actually 'good'.
 

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The set of voltages that you have quoted indicate a faulty volt meter, try another meter.

Clean and tighten the battery terminals and posts.
Check/clean the ground connection, neg battery to body.
Check/clean the ground cable from engine to body.
 

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It does seem that your voltage readings are about 2V too high. Subtract 2 from your posted readings and they look perfectly normal. I would pay attention to the smaller cable that attaches to the main red battery cable; this one supplies power to most of the car, and if it has a high-resistance at the terminal, will result in voltage drop that's worse as more electrical items are turned on.

By the way, RechtsFahren, is that because you have a driver's seat on the right, or you drive on the right, or that you 'drive right'?
 
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