alternator light

[donm]

I have what I think is the original 55 amp alternator and lately after starting the car the red light will remain on for a few minutes. eventually it goes out but is this a sign of potential problems? When the light is out the output shows about 13.6 volts.

This alternator has the voltage regulator mounted on the back. Could the VR be the problem? I've read elsewhere that a "bad diode" could cause this. Where is that located? Is that something I can replace?

[spider2081]

On the Bosch alternators the voltage regulator can be removed while the alternator is on the car. It is a little tedious to replace. Be sure to disconnect the battery before attempting the removal. The alternators brushes are part of the regulator assembly. They may be worn or oil soaked. There are a few things that can contribute to your symptoms. A loose alternator belt would be the first to check.

[RRoller123]

Have the battery load tested as well. Free at AutoZone, Advanced Auto Parts, etc.

[donm]

Thanks, guys. I just ordered a new VR.

[nelsonj]

I recently did a writeup on replacing the VR in-place. I don't know how to link previous posts, but its under electrical titled:
"Replacing Voltage Regulator with Alternator in place" . The thin red straw from a WD 40 can is a big help.

[KevAndAndi]

I tried the VR-replacement route, and it didn't work. YMMV. I ended up handing the alternator and the new VR to my local rebuilder (Italian immigrant, former Spider owner), and now it works and looks like new.