The car wont charge the battery. Alt. good. Then the gauges quit working.

is the engine running at 800 rpm or more.
if engine RPM is way low the Alternator will die out.
trans light , where is that? name it. exactly
lets focus first on the engine, and RPM
does the dash have a tachmeter, ? yes, then use that.
we keep a hand tachometer (optical , ready for no tach cars)
RPM is everything.... maxwells laws. and such.
1: rpm 800 or more all the time. rule 1, do not skip this.
2: belt to ALT not slipping'
3: battery good. terminals on battery cables tight both ends and
NOT PACKED in green corrosion, .
4: alternator case is grounded good.
5: The connection and ALT, all good.
6: you key on, and the dash charge light must turn on,
if not fix that now, on old cars, the dash light , causes the ALT to self excite, if the lamp burns out the alternator boots up DEAD.
or fails every other car starts. (does)
7: new alt is the wrong alt. zillion wrong ones, only 1 works.

There is 4 gauge black/red wire going from te alternator to Fuse #2 in the PDC. The alternator and battery both connect (positive side) at this point. The alternator's path to charge the battery is from the alternator, to this tie point, then to the battery. In the wire, between the alternator and the PDC tie point, is a fusible link. This link may have broken or melted. That would keep the alternator from being able to charge the battery. I would check this wire for continuity and replace the link if necessary.

make sure battery connetions are good and there is a fuseable link from red wire at alt follow wire back to battery youll find it broken

Hi Paula, As both the battery and alternator have been replaced, there are only few remaining reasons why the alternator will not charge. Make sure of the socket connection being fitted correctly and that there is a good connection on each of the connectors inside the connector. Check and make sure the earth earth connection between the battery and the engine is correct and that both ends are tightened correctly. Inspect the 'Alt' fuse in the fuse holder and also the fusible link. Also make sure that the belt is tight. Regards John

The burnt out bulb may be the problem. At least up to '87 the bulb for the alternator light was part of the charging circuit and was used to provide the resistance to excite the alternator to charge. In '88 GM started using the CS alternator, which might be self-exciting.

There isn't much to the charging system on any vehicle. The belt spins the alt copper binding and creates eletrical current. That current goes directly back to the battery. The other wire goes to the gauge in the dash. I would replace the alt. If you said it was intermittent and it tested good at the rebuild shop who is to say that wasn't one of it good times? Easy way to find out how good it is. While the car is running unhook the possitve terminal from the battery. If its good the car will stay running. If it isn't the car wont.

1) check 10A fuse in the batt. juction box (eng. comp.) hot at all times.
2) check the large red battery wire to the alt. for good conn.
3) make sure the alt. is grounded properly
4) gray wire sent from the alt. to the PCM
5) blue wire sent from the PCM to the regulator (alt.)
6) small red wire power frorm the 10A fuse
if all checks out and still not charge replace the alt.

The alternator has a lead wire to the battery. This wire may need replacing . You can replace it with Zero Gauge wire.

I wont list this as a solution, but it seems that working in the area of the alt may have moved around some wiring...the alt may be OK but perhaps an adjacent wire (maybe a ground) is not well connected. Also check crimped on wire loops on alt connectors..they like to corrode at the crimp where it crushes on the actual wire.

start the car,, leave the car on and disconect the battery if the car still on the alt is good but if the car turn off Replace the alt