need for grounds?, help please

[MSCustoms]

Iirc there are 4 pins and he could have repinned the connector.

 

[WVBearcub]

On the connector there is only one wire (brown) from factory. This truck is as basic as you can get. No tach or anything, it started it's life as a 4x4, 5.0 5 speed, vinyl floor, bench seat, crank windows and am/fm radio only WV park service truck. The previous owner swapped in a 5.7. I am going to repin the connector tho, right after I get the new alternator today. The only mod is a self exciting regulator that's a piece of ****, lol. I'm back to the drawing board.

 

[Ken K]

GM had over a dozen years of 1 wire operating alternators, from Buick to Saab. Self exciting regulators is a Delco marine application originally.

Question; Have we ever identified the alternator currently on the vehicle?
Wrong regulator can cause problems as well. Never seen a photo of it.

What is the voltage at the battery and alternator post as measured with a multimeter?

Dido! $20 will get you a digital multi meter. Please get one or borrow.

Test the Battery and Alternators Connection...
#1 Turn DMM to DC, measure voltage at battery while running. Tell us.
#2 Leave DMM to DC, measure voltage at battery while engine off. Try post or bolt and also the terminal that bolts onto it. Tell us. (Side or top post? / Still don't know)
#3 Leave DMM on DC, measure from alt. B+ terminal to Battery B+ while running. Test post or bolt, then connector. Tell us.
(Should be low... 0.50 Vdc or less / This is voltage drop)

(NOTE: Battery positive cables get replaced often. The alternator lead is 10 AWG short wire and comes with a YEL 10AWG crimp-on butt connector to existing alternator wire. These do cause problems. Step #3 will tell if bad or good.)

Did anyone check and make sure the brown wire is in the correct terminal pin at the alternator? Call me paranoid but couldnt the previous owner have moved that wire when trying to fix it?

A schematic will tell you "L" terminal is BRN wire from dash light, hot with key-on, engine-off or running - Bulb-Run-Test - Start.
The "L" terminal on the regulator is marked with a tiny letter seen with connector off. A good flashlight may be needed. (S,F,I,L are common)

Checking / Testing...
#1 Check for the BRN wires position in the plastic connector at the alternator. Compare it to the existing new regulator shows "L" terminal for matching location.
#2 Key-On, Engine-Off, does dash light illuminate? Yes, proceed to next.
#3 Key-On, Engine-Off, connector removed at regulator, use DMM on DC, (use a paper clip carefully as not to damage female terminal)
Does it measure battery available? No? Check wiring back to dash. This can be done with Test light as well. 12 volts, just low current, so will not illuminate any bulb larger than a 194 peanut bulb. The bulb in the dash is a current limiting device in this series circuit at 0.25 amps when hot.

Different engines, other owners, bad butt connector, poor soldered joint, twisted & tapped spliced in harness, frayed, pinched, cut or open wire is normal mistakes that happen.

Knowledge is power. We ask you to get a digital multi meter as it will come in handy for years to come. I tried to provide a simple diagnostic flow chart for you to follow. This will led you to the root cause and a fix. I have lost track of the number of alternators, regulators, trips to the auto store for testing, side terminal or top post battery, and ignore the volt gauge on the dash. I know it's handy, but using a DMM fixes these problems without replacing parts and just guessing.

No one want you to fail with fixing your problem. We are just trying to help. I am guilty of defaulting to "Class Teaching Mode". I apologize.
A shop tech would loose their ass and job if it took this long to get it fixed. The box of "J-Tools" in my electrical cabinet have a "Terminal Removal" kit. This allows me to remove any terminal for testing, moving location or replacement. Yours may have fell victim to this relocation of BRN wire to the wrong spot. We just want to give you the info to fix your issue.

Just remember, the condition of the battery, alternator, regulator and the wires in the circuit is the problem. We are just giving the tools and method to find and fix it. Let us know your findings!

 

[WVBearcub]

GM had over a dozen years of 1 wire operating alternators, from Buick to Saab. Self exciting regulators is a Delco marine application originally.

Question; Have we ever identified the alternator currently on the vehicle?
Wrong regulator can cause problems as well. Never seen a photo of it.



Dido! $20 will get you a digital multi meter. Please get one or borrow.

Test the Battery and Alternators Connection...
#1 Turn DMM to DC, measure voltage at battery while running. Tell us.
#2 Leave DMM to DC, measure voltage at battery while engine off. Try post or bolt and also the terminal that bolts onto it. Tell us. (Side or top post? / Still don't know)
#3 Leave DMM on DC, measure from alt. B+ terminal to Battery B+ while running. Test post or bolt, then connector. Tell us.
(Should be low... 0.50 Vdc or less / This is voltage drop)

(NOTE: Battery positive cables get replaced often. The alternator lead is 10 AWG short wire and comes with a YEL 10AWG crimp-on butt connector to existing alternator wire. These do cause problems. Step #3 will tell if bad or good.)



A schematic will tell you "L" terminal is BRN wire from dash light, hot with key-on, engine-off or running - Bulb-Run-Test - Start.
The "L" terminal on the regulator is marked with a tiny letter seen with connector off. A good flashlight may be needed. (S,F,I,L are common)

Checking / Testing...
#1 Check for the BRN wires position in the plastic connector at the alternator. Compare it to the existing new regulator shows "L" terminal for matching location.
#2 Key-On, Engine-Off, does dash light illuminate? Yes, proceed to next.
#3 Key-On, Engine-Off, connector removed at regulator, use DMM on DC, (use a paper clip carefully as not to damage female terminal)
Does it measure battery available? No? Check wiring back to dash. This can be done with Test light as well. 12 volts, just low current, so will not illuminate any bulb larger than a 194 peanut bulb. The bulb in the dash is a current limiting device in this series circuit at 0.25 amps when hot.

Different engines, other owners, bad butt connector, poor soldered joint, twisted & tapped spliced in harness, frayed, pinched, cut or open wire is normal mistakes that happen.

Knowledge is power. We ask you to get a digital multi meter as it will come in handy for years to come. I tried to provide a simple diagnostic flow chart for you to follow. This will led you to the root cause and a fix. I have lost track of the number of alternators, regulators, trips to the auto store for testing, side terminal or top post battery, and ignore the volt gauge on the dash. I know it's handy, but using a DMM fixes these problems without replacing parts and just guessing.

No one want you to fail with fixing your problem. We are just trying to help. I am guilty of defaulting to "Class Teaching Mode". I apologize.
A shop tech would loose their ass and job if it took this long to get it fixed. The box of "J-Tools" in my electrical cabinet have a "Terminal Removal" kit. This allows me to remove any terminal for testing, moving location or replacement. Yours may have fell victim to this relocation of BRN wire to the wrong spot. We just want to give you the info to fix your issue.

Just remember, the condition of the battery, alternator, regulator and the wires in the circuit is the problem. We are just giving the tools and method to find and fix it. Let us know your findings!

A shop tech isn't a CNA working 60-70 hours a week while trying to fix their vehicle in their free time.
Today I picked up a new alternator (like I said before). I pretty much did a version of painless wiring's 30707 kit, I tested with a multi meter and I'm reading 13.9v, but I'm using an old Dodge coil resistor instead of the 5v resistor which I need, which I will be picking up tomorrow and I will be good.

I mentioned the self exciting regulator in the stock alternator, bad idea because it ran at 17.7v and that was with the headlights and blower motor on high. I did away with that tho.

 

[Ken K]

A shop tech isn't a CNA working 60-70 hours a week while trying to fix their vehicle in their free time.

Hum? Not sure what a "CNA" is? A box with an alternator in it was not available for decades, unless you go to the dealer for a new one. Fixing what I have on a customer vehicle is the way it was done. The regulator is turned on when it get a 12 volt signal thru the 194 bash bulb, which is the same as a 460 ohms resistor. The charging system on GM's have changed several times over the years until electronic controls with load shedding strategies.
The 460 ohm resistor was place in parallel with the dash bulb, therefore, if the build burn't out, the alternator would still work, without regulator damage. Your alternator comes on with the key, before then engine is turning. This is not self exciting. Self exciting is when the alternator come on after the engine is running and RPM's are goosed by choke on high step or IAC operating a cold engine, other than idle.

If the bulb in the dash works, fine. You'l have 12 volts at the brown wire with engine off at the alternator. Add a 460 ohm resistor in series will take the bulbs place completely, so I am not sure exactly what you are doing. A bulb or a 460 ohm resistor is a current limiting device, not a voltage divider. 5 volts on the brown regulator wire, will not allow it work, only battery voltage with the current limited, to keep the regulator from being damaged.

In the "CS" series alternators, they use one wire and the "J" tool used to test the alternator and it's signal. Full fielding the alternator is checking the amperage output. Testing the battery with voltage drop, test wires & terminals at the battery. Testing the battery with a conductance tester shows the condition of the battery. I've had batteries with 12.5 volts but no "CCA". Not doing all of these simple test, is a dis-service to the customer.

Newer alternators have over 26 different regulators that are vehicle specific and are not sold at dealers. Alternators in a box have come a long way and are much better. Hope you got a good one. Best of luck.

 

[smdk2500]

Hum? Not sure what a "CNA" is?

A CNA is a Certified Nurses Aid