Alternator problem

[stvnnelson]

After about an hour or so the alternator off light comes on with negative reading on the amp gauge. Won't reset . Done for the day. After a nights rest the alternator works again, for another hour. Sounds like a heat problem. We have checked the fuse behind the alternator, cleaned the alternator switch and finally changed the voltage regulator. No luck. I guess the alternator is next?

[maules.com]

There is a relay behind subpane/panel joint above the red over voltage light.
Early ones are embedded circuits in a little metal box and later ones are clear lucite type box.
The early ones can short when they get hot.

[stvnnelson]

Thanks Jeremy. This is a 1981 M6 235 so maybe that is the problem.

[stvnnelson]

The factory tells me the relay is in the voltage regulator which we replaced already. My local shop wants to jump the alternator switch on the panel thinking the problem is still in the switch. Maybe we are confused as to the location of the relay?

[maules.com]

The over voltage relay is above the over voltage light at juncture of left panel and subpanel pilot side.

[stvnnelson]

Found it. Part on the way. Thanks Jeremy.