Headlights flickering after replacing alternator

[CrapaTaurusWrecks]

Hello again my friends, It's been a loooong time since I last posted. I've experienced a streak of trouble free driving rarely afforded to a Taurus owner. But alas, something had to eventually give.
I had a squeak coming from the pully side of my 2001 Vulcan flex fuel (96,000 miles). My original thought was the waterpump so I changed it. Still sqweaking, and now leaking! Bought a timing gasket kit and did the job again. No more leak. Also replaced the tensioner but the squeak is still there. In typical "fix it til it's broke" fashion now my battery is draining after about an hour or two on the road or just a few minutes if the A/C is on. So I replaced the Alternator and that solved the charging problem but now the headlights flicker and the fan speed for the A/C goes up and down for 10 minutes or so after starting the car. The battery light on the dash will momentarily pop on with evey flicker.
I've rechecked all the connections and grounds and see nothing wrong. The battery is only a year old. Meter shows 14.7 volts when running and 12.4 when off.
Any ideas where to check to fix this?
Also since I still have the squeak does anyone have a good method of figuring out which pully is bad? Do those stethoscope thingies really work? I'ce sprayed water from a bottle on the pully's but the squeak goes away momentarily no matter which pully I squirt.
Thanks.

[Willyum]

Unless you are absolutely sure you have it pinpointed, the pushrod V-6, Vulcan engine "squeak" is very often the cam sensor driver. For info on this enter into the Google window search "30-S2600"

[shorod]

Since the squeak momentarily goes away when you spray water on the pulleys, you might have a glazed belt or a pulley with a bunch of crud in the grooves. Willyum is correct that the cam synchronizer is often the culprit for a squeak, but that wouldn't go away with the water application to the belt.

Also, the 14.7 Vdc from the alternator is high, you shouldn't get more than 14.4 typically. Does that voltage happen to increase when you turn on the headlights? The check for the source of the flicker, you'll probably need something more like an oscilloscope that samples faster than your typical multi-meter.

Stethoscopes and moving engine parts don't mix well, otherwise they work fine.

-Rod