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LH Lead-Foot · 01-29-2018, 06:13 PM

In the photo posted by VetteVet, it appears to be a Delco 10SI. Identification is crucial first, but if this is your alternator, the regulator is internal AND yes, it has to be grounded. Use the un-used threaded bolt hole and provide a 10 AWG to the engine. I like using star washers on eyelets. The top connector has a small "D" shaped hole under it as pictured. The regulator provides ground to the stator, this is a test window. With engine running, carefully place a pocket screw driver into the hole to touch the case & tab from the regulator. Rev up the engine as you should hear a little whine. Your DMM should show 13.8 - 14.2Vdc. Let's figure out what you have first and what you need to do. The "F" terminal is hot thru the key on, going thru the charge lamp. Depending on the year, they place a 460 ohms resistor in parallel with the lamp to maintain the charging circuit if the bulb goes out. The field coil is the "Y" connect type. The center connection has no voltage if not working. When it is running & working, it provides B+ to the dash lamp. With B+ on both sides of the lamp, it goes out. If their is issues with a diode or something in the alternator, the lamp comes on dim. I have used this terminal to run the electric choke.
Do you have a DMM or analog meter? Are you looking at the dash gauge or meter? Are the battery cable ends clean where the sun does not shine? Are there good ground cables from the battery to engine & chassis? Let's start there with some answers. I taught 31 different classes, 6 of those being electrical classes for ACDelco, with #6 being lab scopes.
As for wire size (AWG) yes, current is measured in amps, but the length of the circuit determines the size of the wire. Most 4 -10 amp circuits operate with 20 gauge wire on GM's the last 30 years. As for a good relay/fuse center, go for the passengers side IP relay center from Buick LeSabre, Park Ave thru 1990-1999. Older one had 0.250" relay terminals, then they switched to "Micro" relays using 2.80m or called 280. The relay/fuse center is behind the glove box, with the ECM, theft module (Pass-key) and lamp module and is rectangular in shape while locations for 12 relays & 12 fuses. Good bone yard find for $10 of less.

01-29-2018, 06:13 PM	#15
LH Lead-Foot Registered User Join Date: Jan 2018 Location: Omaha, NE. Posts: 214	Re: Charging issues In the photo posted by VetteVet, it appears to be a Delco 10SI. Identification is crucial first, but if this is your alternator, the regulator is internal AND yes, it has to be grounded. Use the un-used threaded bolt hole and provide a 10 AWG to the engine. I like using star washers on eyelets. The top connector has a small "D" shaped hole under it as pictured. The regulator provides ground to the stator, this is a test window. With engine running, carefully place a pocket screw driver into the hole to touch the case & tab from the regulator. Rev up the engine as you should hear a little whine. Your DMM should show 13.8 - 14.2Vdc. Let's figure out what you have first and what you need to do. The "F" terminal is hot thru the key on, going thru the charge lamp. Depending on the year, they place a 460 ohms resistor in parallel with the lamp to maintain the charging circuit if the bulb goes out. The field coil is the "Y" connect type. The center connection has no voltage if not working. When it is running & working, it provides B+ to the dash lamp. With B+ on both sides of the lamp, it goes out. If their is issues with a diode or something in the alternator, the lamp comes on dim. I have used this terminal to run the electric choke. Do you have a DMM or analog meter? Are you looking at the dash gauge or meter? Are the battery cable ends clean where the sun does not shine? Are there good ground cables from the battery to engine & chassis? Let's start there with some answers. I taught 31 different classes, 6 of those being electrical classes for ACDelco, with #6 being lab scopes. As for wire size (AWG) yes, current is measured in amps, but the length of the circuit determines the size of the wire. Most 4 -10 amp circuits operate with 20 gauge wire on GM's the last 30 years. As for a good relay/fuse center, go for the passengers side IP relay center from Buick LeSabre, Park Ave thru 1990-1999. Older one had 0.250" relay terminals, then they switched to "Micro" relays using 2.80m or called 280. The relay/fuse center is behind the glove box, with the ECM, theft module (Pass-key) and lamp module and is rectangular in shape while locations for 12 relays & 12 fuses. Good bone yard find for $10 of less.