Alternator OR BATTERY
Thread Starter
Racer
Joined: Mar 2003
Posts: 329
Likes: 0
From: GARY IN
Alternator OR BATTERY
I have 98 c5 the volts read 13.1 to 13.4 on the highway when i am in the city and its hot it drops to 12.2 to 12.6 is the alt going bad or is the battery getting weak dont wont to get caught on a trip and alt goes out.
Pro
Joined: Sep 2007
Posts: 735
Likes: 7
From: Bucks County Pa
Could be bad alt or bad battery
Hi, How many miles on the car/alt, how old is the battery, what is your driving pattern,(dd or occaisional). The readings you are getting do seem low. When things heat up under the hood the regulator cuts back on alt output, hence the lower city when hot readings. You could have one or a few different problems.
1, It may be as simple as a battery going bad, highly sulphated and not able to take a full charge , which fools the system to cut back on output.
2, The cables may be loose or dirty.
3, The regulator may be going bad.
4, The alternator could be going bad.
If the battery is more than a few years old I would look there first, after I verified that all the cables were clean and tight,(both sides at the battery, starter, and fuse block, also the connections going to the alternator.
You can load test the battery to confirm that it is in fact fully chargeable.
Then field test the alternator to see if it is able to output at least 15 volts.
Good Luck
1, It may be as simple as a battery going bad, highly sulphated and not able to take a full charge , which fools the system to cut back on output.
2, The cables may be loose or dirty.
3, The regulator may be going bad.
4, The alternator could be going bad.
If the battery is more than a few years old I would look there first, after I verified that all the cables were clean and tight,(both sides at the battery, starter, and fuse block, also the connections going to the alternator.
You can load test the battery to confirm that it is in fact fully chargeable.
Then field test the alternator to see if it is able to output at least 15 volts.
Good Luck
Pro
Joined: May 2008
Posts: 596
Likes: 2
From: Houston Texas
Are your readings from the DIC or actual on the battery posts?
Pro
Joined: May 2008
Posts: 596
Likes: 2
From: Houston Texas
you may have the same issue as me-the number on the dash is about 0.6V lower than the actual on the battery.That would indicate bad connection between the battery post (positive) and the inside fuse box from which the dash is supplied.I'll have more info tonight...
