Well i have a 91 VW diesel Golf. At high RPM....which is not that high since its Diesel, anyway the batt light comes on and the lights go dim and all that crap. Then when I let off the gas everything is fine. Also at highway speed around 110 Km/h the light comes on and off every 10 seconds or so. All is fine when Im driving at low speed and RPM. Any ideas? Im thinking it may be the Voltage regulator. Or should I just swap alternators. By the way the battery is new.

Thanks

 

Apparently, there is no voltmeter in the car, right? A voltage reading at those operating conditions might be helpful, and you can easily rig a test meter to the lighter socket (or whatever source) to monitor that while driving. That information could be very revealing.

If the voltage falls off at higher RPMs, you may have a regulator issue or mechanical damage to the alternator which only becomes apparent under the higher centrifugal forces at that RPM, such as like a failing field winding (not stator, but FIELD or rotor), or possibly field brushes that bounce off the slip rings at higher RPM due to an out-of-round condition. Getting the alternator tested might be a good idea if you can find a test facility that can spin the unit up to the max RPM.

 

Thanks VADER, your right no VM but ill righ the lighter. By the way do you know if the over the counter rebuild kits contain all that is neccesary to do my own rebuild?

Thanks