New Alternator not Charging New battery!
Thread Starter
Trial User
Joined: May 2015
Posts: 2
Likes: 0
New Alternator not Charging New battery!
my old alternator I thought, was not recharging my battery. Instead of getting it tested, I assume that is was the alternator so I bout I new one with a new battery as well. The battery tested bad. Once new parts was installed, I still came into trouble down the road at night the gauges quit working lights went out, then car just simply died. I have check the alt fuse and it seems to be ok. Only thing else I know to do is to buy new wires from the alternator to the battery...... Has anyone came across this issues and can help me out, maybe its something simple that I am over looking. Any advices or solutions any has would be greatly appreciated! 2003 civic ex coupe
Global Moderator
Joined: Jul 2004
Posts: 6,060
Likes: 514
Re: New Alternator not Charging New battery!
Under-dash fuse no. 4 (10A) and the Blk/Yel (IG) wire supplies the ignition input that turns on the alternator/regulator assembly. I just wanted to make sure you were at least checking the correct fuse.
A voltmeter alone can greatly help you narrow or determine the area of issue. Since a multimeter includes more than just a voltmeter, it is worthwhile to have for other tests and uses down the road (not only for your car). An inexpensive multimeter should suffice for general testing purposes.
Here are a couple of tests I wrote up:
1. At the alternator's light green connector plug, disconnect the plug. Then test if there is voltage (battery power ~ 12 volts) at the Blk/Yel wire terminal with the ignition switch in position II (ON). The voltmeter's red lead will be on the connector terminal for the Blk/Yel wire; and the voltmeter will be on body ground (e.g., a bolt on the car, body chassis, or negative battery post).
The Blk/Yel wire supplies the ignition input that turns on the alternator/regulator assembly. If there is no, low, or intermittent voltage coming through the Blk/Yel wire to the alternator, the alternator will not charge or have problems charging.
(A Blk/Yel wire is a wire with black colored insulation with a yellow stripe running through it.)
2. If there is ~ 12 volt at the Blk/Yel wire from the first test, then test the voltage at the alternator output cable (Wht cable) at the under-hood fuse box (T101). This alternator cable supplies current to the battery.
You can also check the connector (T102) at the alternator, to see if it is the same reading as at T101.
Check the voltage with it idling, then raise the engine speed to 2,000 rpm and hold it there, and see if the voltage increases.
A voltmeter alone can greatly help you narrow or determine the area of issue. Since a multimeter includes more than just a voltmeter, it is worthwhile to have for other tests and uses down the road (not only for your car). An inexpensive multimeter should suffice for general testing purposes.
Here are a couple of tests I wrote up:
1. At the alternator's light green connector plug, disconnect the plug. Then test if there is voltage (battery power ~ 12 volts) at the Blk/Yel wire terminal with the ignition switch in position II (ON). The voltmeter's red lead will be on the connector terminal for the Blk/Yel wire; and the voltmeter will be on body ground (e.g., a bolt on the car, body chassis, or negative battery post).
The Blk/Yel wire supplies the ignition input that turns on the alternator/regulator assembly. If there is no, low, or intermittent voltage coming through the Blk/Yel wire to the alternator, the alternator will not charge or have problems charging.
(A Blk/Yel wire is a wire with black colored insulation with a yellow stripe running through it.)
2. If there is ~ 12 volt at the Blk/Yel wire from the first test, then test the voltage at the alternator output cable (Wht cable) at the under-hood fuse box (T101). This alternator cable supplies current to the battery.
You can also check the connector (T102) at the alternator, to see if it is the same reading as at T101.
Check the voltage with it idling, then raise the engine speed to 2,000 rpm and hold it there, and see if the voltage increases.
Honda-Tech Member
Joined: Jan 2015
Posts: 10
Likes: 0
Re: New Alternator not Charging New battery!
Check the voltage drop of the power wire.you will need a multimeter set it to 12v DC. Put the positive on the alternator 12v wire. Put the negative lead on the battery positive. The reading should be .50v (1/2 of a volt) or less. If it is more you have high voltage drop replace the cable
Trial User
Joined: Dec 2020
Posts: 1
Likes: 0
Re: New Alternator not Charging New battery!
my old alternator I thought, was not recharging my battery. Instead of getting it tested, I assume that is was the alternator so I bout I new one with a new battery as well. The battery tested bad. Once new parts was installed, I still came into trouble down the road at night the gauges quit working lights went out, then car just simply died. I have check the alt fuse and it seems to be ok. Only thing else I know to do is to buy new wires from the alternator to the battery...... Has anyone came across this issues and can help me out, maybe its something simple that I am over looking. Any advices or solutions any has would be greatly appreciated! 2003 civic ex coupe
Trial User
Joined: Apr 2021
Posts: 1
Likes: 1
Re: New Alternator not Charging New battery!
my old alternator I thought, was not recharging my battery. Instead of getting it tested, I assume that is was the alternator so I bout I new one with a new battery as well. The battery tested bad. Once new parts was installed, I still came into trouble down the road at night the gauges quit working lights went out, then car just simply died. I have check the alt fuse and it seems to be ok. Only thing else I know to do is to buy new wires from the alternator to the battery...... Has anyone came across this issues and can help me out, maybe its something simple that I am over looking. Any advices or solutions any has would be greatly appreciated! 2003 civic ex coupe
Trending Topics
Honda-Tech Member
Joined: Jun 2022
Posts: 2
Likes: 0
Re: New Alternator not Charging New battery!
Under-dash fuse no. 4 (10A) and the Blk/Yel (IG) wire supplies the ignition input that turns on the alternator/regulator assembly. I just wanted to make sure you were at least checking the correct fuse.
A voltmeter alone can greatly help you narrow or determine the area of issue. Since a multimeter includes more than just a voltmeter, it is worthwhile to have for other tests and uses down the road (not only for your car). An inexpensive multimeter should suffice for general testing purposes.
Here are a couple of tests I wrote up:
1. At the alternator's light green connector plug, disconnect the plug. Then test if there is voltage (battery power ~ 12 volts) at the Blk/Yel wire terminal with the ignition switch in position II (ON). The voltmeter's red lead will be on the connector terminal for the Blk/Yel wire; and the voltmeter will be on body ground (e.g., a bolt on the car, body chassis, or negative battery post).
The Blk/Yel wire supplies the ignition input that turns on the alternator/regulator assembly. If there is no, low, or intermittent voltage coming through the Blk/Yel wire to the alternator, the alternator will not charge or have problems charging.
If I’m not getting power with the black and yellow cord how do I fix it ?
(A Blk/Yel wire is a wire with black colored insulation with a yellow stripe running through it.)
2. If there is ~ 12 volt at the Blk/Yel wire from the first test, then test the voltage at the alternator output cable (Wht cable) at the under-hood fuse box (T101). This alternator cable supplies current to the battery.
You can also check the connector (T102) at the alternator, to see if it is the same reading as at T101.
Check the voltage with it idling, then raise the engine speed to 2,000 rpm and hold it there, and see if the voltage increases.
A voltmeter alone can greatly help you narrow or determine the area of issue. Since a multimeter includes more than just a voltmeter, it is worthwhile to have for other tests and uses down the road (not only for your car). An inexpensive multimeter should suffice for general testing purposes.
Here are a couple of tests I wrote up:
1. At the alternator's light green connector plug, disconnect the plug. Then test if there is voltage (battery power ~ 12 volts) at the Blk/Yel wire terminal with the ignition switch in position II (ON). The voltmeter's red lead will be on the connector terminal for the Blk/Yel wire; and the voltmeter will be on body ground (e.g., a bolt on the car, body chassis, or negative battery post).
The Blk/Yel wire supplies the ignition input that turns on the alternator/regulator assembly. If there is no, low, or intermittent voltage coming through the Blk/Yel wire to the alternator, the alternator will not charge or have problems charging.
If I’m not getting power with the black and yellow cord how do I fix it ?
(A Blk/Yel wire is a wire with black colored insulation with a yellow stripe running through it.)
2. If there is ~ 12 volt at the Blk/Yel wire from the first test, then test the voltage at the alternator output cable (Wht cable) at the under-hood fuse box (T101). This alternator cable supplies current to the battery.
You can also check the connector (T102) at the alternator, to see if it is the same reading as at T101.
Check the voltage with it idling, then raise the engine speed to 2,000 rpm and hold it there, and see if the voltage increases.
Global Moderator
Joined: Jul 2004
Posts: 6,060
Likes: 514
Global Moderator
Joined: Jul 2004
Posts: 6,060
Likes: 514
Re: New Alternator not Charging New battery!
The Blk/Yel wire is supposed to only have power when the ignition switch is in the ON or running positions.
Describe in detail what exactly is happening with your car? Also, confirm the year and model.
Describe in detail what exactly is happening with your car? Also, confirm the year and model.
Honda-Tech Member
Joined: Mar 2019
Posts: 25
Likes: 1
Re: New Alternator not Charging New battery!
Wow idk what it is idk if now these older Hondas are running into this electrical problem with the ALT, just had my OEM tested it tested bad voltage regulator so we replaced with reman, that left us stranded and tested bad on all 3 testing parameters, bought brand new unused duralast and it started doing the same thing, which was all the gauges cut out and the car would stall/not start without a jump. We took out the new ALT bench tested and its good, we bought a new battery and it worked for a day and left us stranded with the same issues. Did you figure this out? I gave us and currently have the car at a shop we're they're gonna look at it tomorrow and I'll update, I really thing it's a grounding issue but idk why the car would start acting like this out of nowhere just because the lights were left on, because someone went through my car and turned them on....
Trial User
Joined: Mar 2025
Posts: 1
Likes: 0
Re: New Alternator not Charging New battery!
Sorry to have to resurrect the thread bulk have a 2005 MT Civic, new alternator, replaced fried group 51R battery with a bigger group 24 AGM battery. The new alternator is making 12.44v at idle, 12.34v with all loads on. No battery light since alternator replacement. Checked all fuses, and wires - no blown fuses, no broken wires or grounds, no rust. With ignition in ON position, Im getting 12.45v at the alternator big terminal and 12.24v at the black wire with yellow stripe at 4-pin terminal. I dont know where else to look, I took apart the harness on top of the valve cover - no issues at all.
Anyone know what Im missing ?
Anyone know what Im missing ?
Thread
Thread Starter
Forum
Replies
Last Post
RVMIRXZem1
Honda Civic / Del Sol (1992 - 2000)
4
Oct 16, 2018 04:41 AM
EJason
Honda Civic / Del Sol (1992 - 2000)
4
Mar 5, 2009 10:19 AM
lmike6453
Acura Integra
16
Jan 16, 2009 06:55 PM
Honduh Chicken
Honda CRX / EF Civic (1988 - 1991)
5
Nov 28, 2004 06:51 PM