droldsmorland

Grounds....grounds.... grounds. Check, clean & seal with clear ignition sealer...all of them. The Negative & Positive cables need to be serviceable and exhibit low resistance. Check the connections at both ends. Any car guy should buy a decent Volt Ohm meter if you dont already have one? Also have your battery load tested. You may have a battery that has bad cells. Surface charge is 12-13vdc but as soon as its loaded it falls on its azz. If your alternator is dealing with bad grounds and a bad battery it will give some of these symptoms. A simple restive battery load tester isnt expensive. It will show charging voltage too.

87oldscutty

I drove my Cutlass to work this morning. All was somewhat ok till I was about 5 minutes to work. The charge light came back on and wouldn't go back out like before. I'm getting frustrated with the car. I have checked my wires and they seem ok and the belts are good. I don't know what else to do. My second replacement alternator should be in today and will replace it when I get home. If that don't fix it then I am totally at a loss.

Miles71

Send some pictures if you can. #1 Belt layout, #2 Back of Alternator, #3 Battery area. Maybe a picture will show us what might be missing?

Check to see if you have a braided ground strap, running from the engine block to the firewall. Find and clean connections. A missing engine block ground will cause light flickering as the engine shakes.

I am not familiar with the wiring of an 87 olds, however, a loose ground in the instrument panel, could cause a false alternator light.

If possible,try to temporarily mount a digital volt meter to your Dash or console (clear packingtape). Connect the DVM leads to a good Ground screw and the positive to an easy to find wire, such as the Radio wire or fuse panel. This will allow you to see the voltage while you are driving.
Voltage at speed:

All-off (turn off headlights, Radio, AC, etc)
Running at Idle,(All-off), over 13.0 (preferably 13.8 range)
At speed 30+(All-off) over 13.5, should be 13.8 to 4.1 depending on accuracy of meter and connection location.

Did you ever get your battery officially tested? What were the results?

joe_padavano

It's no different than on earlier cars. The alternator light circuit doesn't rely on any instrument panel ground. The GEN light has key-switched +12V applied on one side of the lamp. The other side of the lamp is connected to the field terminal on the alternator. When the alternator is not charging, that terminal is grounded in the alternator, causing the light to be on. When the alternator is charging, the terminal also sees +12V (actually, 13.8 in both cases) and the light is off. Now, a dirty or loose connector somewhere in that light wiring can cause a problem, though usually it manifests itself as a dim light.

Now, all of this is moot if the O.P. really is getting less than 13.8V directly out of the alternator.

87oldscutty

I can put the gas pedal to the floor and 80% of the time the light will go out so I am stumped. Does the brown wire connected to my alternator go to the charge light?

joe_padavano

Yes.

Professur

When a generator is tapped, it electrically brakes the motor. That it started squealing when the voltage jumped into the acceptable range means 2 things. One, the belt wasn't tightened correctly ... and 2, that when it wasn't squealing, there was no demand for power from it. To me, that points right to the voltage regulator.

87oldscutty

Ok cause if it don't split somewhere I will run a new wire or add a gauge. Does anyone recommend doing this

87oldscutty

To my own stupidity the squealing was my fan belt was loose. I am just stumped on why I can't figure this out. I'm usually good at these things.

MDchanic

Yup.

- Eric

87oldscutty

So it don't T off anywhere

stellar

Don't T off. Let us know what happens after you replace the alternator again since you have one on the way. If the same symptoms persist, have a volt meter handy and we will work it out.

87oldscutty

Oh I feel like a mo-ron! Changed the alternator and so far the light has stayed off. I'm thankful for your help and do appreciate it.