Disc Alt/Bat wire while running-Can I?
Thread Starter
Pro
Joined: Mar 1999
Posts: 532
Likes: 0
From: Cleveland Ohio
Guys, Can I disconnect, with the engine running, the one wire at the rear of the alternator without creating any additional problems? Also, can I disconnect the battery positive cable while the engine is running without causing a problem. I'm trying to see if the alt is working. The 11.5 volts at the alt may be battery voltage back feeding to the alt. I'm attempting to isolate and check. I figure if I disconnect the battery and the engine stops I'll know the alt is shot, regardless....Frank
Burning Brakes
Joined: Dec 2000
Posts: 1,161
Likes: 0
From: Orangeburg, NY
You can disconnect either wire, but it could casuse damage to; the alternator, regulator, inline fuses, the programmer, control mdule, etc. It use to be done years ago when electronics were simple, and no computerization. But now it is not recommended
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
You won't hurt anything by disconnecting the battery or the alternator output with the engine running. Try the alternator first and be careful not to touch your wrench to ground because the red wire goes to the battery through a fusible link and you could blow the fusible link. The disconnected alternator should read 14 volts or so, if not, its defective. The car could still keep running with an 11.5 volt alternator output, but it will never charge the battery and the alternator should be replaced.
