unusual electrical problem
 

Tonight while driving my 80 SC an electrical problem occurred.Intermittently the seatbelt light would come on the tach would jump & the headlights would get very bright.I think it
burned out the high beams.

Has anyone experienced this problem?

Check the voltage output from the alt. Might have a bad regulator or bad connector in the charging system.

bizerk voltage regulator.

Failing Voltage regulator ... high Voltage spikes!

Check/monitor your system Voltage ... plan on getting a new Voltage regulator, soon!

The sooner the better. The more you run with those symptoms the greater the risk of frying additional electrical systems (expensive).

After reading Jim Thorusen's troubleshooting guide on this site I removed the alternator and found the D+ connection to the voltage regulator loose.The regulator looks at D+ to determine excitation current in the alternator.If the regulator sees low or 0 voltage at D+ it increases excitation current which raises output voltage.Anyway I put the alternator back in and drove several test miles with no voltage spike problems.

Note;my alternator was a Valeo with internal regulator.

Thanks for all the help!