bad alternator??
#11
12-17-2021 | 09:43 AM
Administrator
Joined: Apr 2010
Posts: 82,830
Likes: 3,435
From: Clayton MI
A couple of weeks ago truck wouldn't start. Battery was dead. Threw in a new battery and it started. The next morning the new battery was dead (overhead map light switch). Jumped it, let it charge a few from the other car, then took the negative cable off and truck died. Onto a new alternator. Usually on older vehicles when the battery dies the alternator isn't too far behind or vice versa.
#12
12-17-2021 | 10:52 AM
Veteran
Joined: Jul 2013
Posts: 281
Likes: 43
From: TN
A couple of weeks ago truck wouldn't start. Battery was dead. Threw in a new battery and it started. The next morning the new battery was dead (overhead map light switch). Jumped it, let it charge a few from the other car, then took the negative cable off and truck died. Onto a new alternator. Usually on older vehicles when the battery dies the alternator isn't too far behind or vice versa.
#13
12-17-2021 | 09:08 PM
Champion
Joined: May 2019
Posts: 4,461
Likes: 601
From: S.W. Indiana
Disconnecting the battery while running is a simple way to destroy ANY alternator equipped system. Not only will it freak a computer out, pre-computer cars from the early 1960's and up have alternators. Unlike generators, which you CAN disconnect, there are NO permanent magnets in an alternator. There IS a diode. It's a little bitty thing but critical to the alternator working. Unhooking the battery while running is like cross jumping a battery. It can blow that diode out right away. You now have no way to change the AC the alternator makes to the DC current it needs.
#14
12-17-2021 | 09:38 PM
Veteran
Joined: Jul 2013
Posts: 281
Likes: 43
From: TN
Disconnecting the battery while running is a simple way to destroy ANY alternator equipped system. Not only will it freak a computer out, pre-computer cars from the early 1960's and up have alternators. Unlike generators, which you CAN disconnect, there are NO permanent magnets in an alternator. There IS a diode. It's a little bitty thing but critical to the alternator working. Unhooking the battery while running is like cross jumping a battery. It can blow that diode out right away. You now have no way to change the AC the alternator makes to the DC current it needs.