View Single Post
Old 10-14-2008, 02:54 PM   #3
Lil bastard
Registered User
Lil bastard's Avatar
Join Date: Feb 2008
Location: Du Monde
Posts: 2,199
As said, most likely the starter switch (ignition). It still could be an alternator failure, even though you were able to drive 300 mi.But, it's easy enough to rule out the alternator. First, the alternator could have partially failed say at 275 mi. and the battery was sufficiently charged to get you the next 25 mi.

Use a DMM and, engine running - lights on, check the DC voltage between the battery terminals - it should read 13.5-14.5 VDC, if other, your alternator is on it's way out. Alternators often fail progressively rather than all at once. It contains 3 sets of diodes which can fail singly changing the output voltage to the battery without a total failure. I'd do this simple check before ordering any other parts.
1990 Porsche 964 Carrera 4 Cabriolet
1976 BMW 2002
1990 BMW 325is
1999 Porsche Boxster
(gone, but not forgotten)

Never drive faster than your Guardian Angel can fly!
Lil bastard is offline   Reply With Quote