Any ideas on what this means? Regulator?

I checked the belt tension, and it's within specs.

It was making some unpleasant noise for a while then stopped.

Might be the greatest "well, duh!" of all time, but anyone who knows what to do about it, sound off please!

 

MOST of the time your SES goes off, it's going to be emissions related.

It looks like your alternator is not charging, and you may need a new one. Get it checked at your local auto store.

 

If you have a voltage gauge the system will not set off a charging light because it is not equiped with one. Prior to starting the gauge should read between 12.2 and 1.8 volts after starting it should read above 13. if it is not then its time to remove the alternatore and take it to a local parts store and have it tested. If it tests ok then it is time to look at all of your electrical connections and your terminals to make sure there is not a corrosion buildup.

Sean

 

Another thing to look for is dirty batt connectors & chassis grounds. Dirty/corroded(sp?) connections cause resistance & a loss of juice.

Crappy connections can give false impressions of something else being wrong.. not to say your alt might not be dieing,, but making sure all your connections are clean & tight is free & a easy start.

 

The alt. is most likely BAD. That noise you heard is probably the rear bearing, it is the most common problem with the CS series alternators. If you are prior to 86 you have a 10Si type. Both are fairly easy to repair if you are handy. How you choose is up to you but unless you have a drive belt that is falling off at 10.5 volts you are running off of the battery. Point of interest alternators will NOT trigger a trouble code unles voltage goes as low as to cause ECM to become unstable and it will usually stop running before that happens.