I did perform an alternator load test. I did not think to turn on the wipers, high beams, or full fan
I turned on:
a/c to auto (the fan went to about 1/2 speed)
rear window defroster
front driver seat heater max heat
headlights and fog lights
The readout started at 13.8 V and with each system it went down to 13.4 V
Reading some other threads on alternators, it sounds like maybe the brushes in the alternator are getting old. Records show that the alternator was changed at 78,681 at a BMW dealership. Car is at 135,000 now.
Am I in the right direction?
2003 BMW 540i A M-Sport with factory Navigation and CD changer; winter package
1997 Toyota Landcruiser 40th anniversary edition