98 corvette alternator issue
Le Mans Master
Joined: Apr 2002
Posts: 6,927
Likes: 3
From: Glendale NY
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18- '19
This should help. The 97-98 Schematics should be the same:
There are critical voltages that must be present for the alternator to work properly. Without doing voltage testing,, this will get expensive real quick!
There are some critical connections and wireing on the starter solenoid that effect alternator operation. CHECK THAT before you get too far into this issue.
BC
There are critical voltages that must be present for the alternator to work properly. Without doing voltage testing,, this will get expensive real quick!
There are some critical connections and wireing on the starter solenoid that effect alternator operation. CHECK THAT before you get too far into this issue.
BC
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Read the BATT terminal on the BACK of the alternator to ground with the engine OFF and see what it reads.
It should read the same as the battery POSITIVE terminal to ground with the engine OFF.
THEN:
Read the BATT terminal on the BACK of the alternator to ground with the engine running and see what it reads.
It should read the same as the battery POSITIVE terminal to ground with the engine running.
If you read the battery POSITIVE terminal to the alternator BATT terminal with a meter and the connection at the starter solenoid is 100% good, you should read ZERO VDC. If you have a voltage reading, the solenoid connection is poor/compromised:
Connections on Solenoid
If theres a difference between what the battery voltage reads at the battery and what the volt meters in the dash reads,, the delta is caused by dirty / defective contacts in your ignition switch!
-C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
It should read the same as the battery POSITIVE terminal to ground with the engine OFF.
THEN:
Read the BATT terminal on the BACK of the alternator to ground with the engine running and see what it reads.
It should read the same as the battery POSITIVE terminal to ground with the engine running.
If you read the battery POSITIVE terminal to the alternator BATT terminal with a meter and the connection at the starter solenoid is 100% good, you should read ZERO VDC. If you have a voltage reading, the solenoid connection is poor/compromised:
Connections on Solenoid
If theres a difference between what the battery voltage reads at the battery and what the volt meters in the dash reads,, the delta is caused by dirty / defective contacts in your ignition switch!
-C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
Thread Starter
Intermediate
Joined: Sep 2011
Posts: 47
Likes: 0
Read the BATT terminal on the BACK of the alternator to ground with the engine OFF and see what it reads.
It should read the same as the battery POSITIVE terminal to ground with the engine OFF.
THEN:
Read the BATT terminal on the BACK of the alternator to ground with the engine running and see what it reads.
It should read the same as the battery POSITIVE terminal to ground with the engine running.
If you read the battery POSITIVE terminal to the alternator BATT terminal with a meter and the connection at the starter solenoid is 100% good, you should read ZERO VDC. If you have a voltage reading, the solenoid connection is poor/compromised:
Connections on Solenoid
If theres a difference between what the battery voltage reads at the battery and what the volt meters in the dash reads,, the delta is caused by dirty / defective contacts in your ignition switch!
-C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
It should read the same as the battery POSITIVE terminal to ground with the engine OFF.
THEN:
Read the BATT terminal on the BACK of the alternator to ground with the engine running and see what it reads.
It should read the same as the battery POSITIVE terminal to ground with the engine running.
If you read the battery POSITIVE terminal to the alternator BATT terminal with a meter and the connection at the starter solenoid is 100% good, you should read ZERO VDC. If you have a voltage reading, the solenoid connection is poor/compromised:
Connections on Solenoid
If theres a difference between what the battery voltage reads at the battery and what the volt meters in the dash reads,, the delta is caused by dirty / defective contacts in your ignition switch!
-C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
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Thread Starter
Intermediate
Joined: Sep 2011
Posts: 47
Likes: 0
Thanks guys for all your help the whole thing was a starter isuue had the chev dealer look at he replaced the starter now i have 14.0 at the alternator 13.90 at the battery (runing) the dash still hold at 12.5 to 12.8 but the battery is now charging that god still want to fine out why it say 12.5
Thread Starter
Intermediate
Joined: Sep 2011
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Tony
I'll have to check my readings.....when it stops raining.
Do you still get the, "charge system fault" reading on the DIC?
Are all these scenario's at idle or at speed? Sounds like you are checking them at idle.
Did you purchase the Valero, made in France, part number 10246634? This is the only alternator that has the built in monitor circuit that will work in our year car. (Bill Curlee, Evil Twin)
I really hope you get this straightened out, I hate it when I can't drive my car.
I'll have to check my readings.....when it stops raining.
Do you still get the, "charge system fault" reading on the DIC?
Are all these scenario's at idle or at speed? Sounds like you are checking them at idle.
Did you purchase the Valero, made in France, part number 10246634? This is the only alternator that has the built in monitor circuit that will work in our year car. (Bill Curlee, Evil Twin)
I really hope you get this straightened out, I hate it when I can't drive my car.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Plain and simple!! Rebuild or replace the SWITCH part and you will see very close to actual battery voltage on your meters.
Thread Starter
Intermediate
Joined: Sep 2011
Posts: 47
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i know your right going to check the fuse frist are a number like eng ing fuse 19 will it say it on the fuse
