94 Buick Regal - Headlight & Ignition Issue

This is a Repost of my :
I have a '94 Buick Regal Limited with a 3.8 engine. A week ago my engine started normally, but hesitated and the headlights went dim when I turned the lights on. These are the things I have done this past week:
1) Checked the Battery and it is charged
2) Made sure the battery cables were clean and tight
3) Verified the connections to the solenoid starter were clean and tight
4) Checked the small wire on the solenoid starter with a voltmeter and it was good

I have been able to jump start the car sometimes, but it dies, most of the time, whenever I turned on the headlights. I have also been able to start the car by turning the headlight switch off and on many times until the dashboard indicator lights were bright. The engine always starts when the lights are bright. I am thinking that the headlight switch is bad. Is a bad headlight switch a possible cause for the ignition problems? Any other possible causes?
Thanks,

Dan

You may have an issue with the alternator so get it checked out or tested. Also, you can check the output with a DMM once it is running.

Did you get the battery tested instead of assuming it is good. It may have a bad cell or low specific gravity? Did you check the battery voltage going across the positive and negative terminals with a DMM (meter). I so what was it reading?

I took the battery to Sears and had them check it out. It was good and only required a 6 minute charge. Is there a way to check the alternator without removing it? I will see about getting the voltage across the battery terminals and let you know.
Thanks,

Dan