alternator not charging

[allgravey20]

My alternator on my 01 ex sport will not charge. I have 2 others that were all tested at autozone and tested good. But none of them will work. I have battery voltage coming out of the plug that goes into the alternator, but the wire that goes to battery is not putting out anything. I have tried all alternators on this ex with no luck and all of them work on my other ex. Not sure if there is a fuse or fuseable link somewhere or what the issue is.since i have voltage in. Need some assistance!

 

[koda2000]

does your BATT light bulb work during the bulb check?

 

[allgravey20]

Yes

 

[1998Exp]

Not sure about the exact configuration of your 2001, but there should be two fuses involved:
1) 175A Megafuse that connects the alternator output wire to the battery wire. Should be mounted on the outside of the power distribution box in the engine compartment.
2) A smaller, 30A fuse inside the power distribution box (#14 on my 1998), which provides battery power to the alternator's field winding regulator.

From your description, the smaller 30A fuse seems intact, and the problem is likely to be the megafuse. Check carefully for shorts in the wiring before you replace it -- it's not going to be fun when the replacement blows up too.

My alternator on my 01 ex sport will not charge. I have 2 others that were all tested at autozone and tested good. But none of them will work. I have battery voltage coming out of the plug that goes into the alternator, but the wire that goes to battery is not putting out anything. I have tried all alternators on this ex with no luck and all of them work on my other ex. Not sure if there is a fuse or fuseable link somewhere or what the issue is.since i have voltage in. Need some assistance!

 

[allgravey20]

I took apart what everybody says is a mega fuse and it's just two connections with a chunk of metal bolting them together. There is no way that could be bad if they are joined together with a piece of metal. The 30 amp fuse inside is also good and we took the battery out of my other ex as well so we had a good alternator and a good battery and still nothing. If it was the mega fuse like everybody has said on different threads I would still be getting voltage out of the terminal on the alternator wouldn't I?

 

[Flash]

If it was the mega fuse like everybody has said on different threads I would still be getting voltage out of the terminal on the alternator wouldn't I?

Yes, you would. You said that was happening in your first post.

I have battery voltage coming out of the plug that goes into the alternator, but the wire that goes to battery is not putting out anything.

Check the megafuse with a continuity tester first.
Check for voltage going into the alternator at the field winding.
If there is voltage coming out of the alternator but not coming out at the battery and the megafuse is good then look at replacing the battery leads.

EDIT
Looking at your post again I think you mean that there's voltage going in the field winding but not coming out at the battery?
Check for voltage coming out at the back of the alternator.

 

[allgravey20]

I have no voltage coming out of the post of alternator (to megafuse and battery) the alternator plug has battery voltage coming out on both wires.

 

[SoNic67]

...the alternator plug has battery voltage coming out on both wires.

You have ground issues (alternator body, ground strap to battery).

 

[allgravey20]

I will redo all of the grounds tonight or tomorrow (weather permitting) and see if that works. I "assumed " that since i could pull a reading off of the alternator housing with the multimeter that it was grounded good.

 

[SoNic67]

Measure between housing and battery negative post, see if you have zero.

 

[koda2000]

As the alternator is securely bolted to the engine block, I doubt that it's ground is the problem. You can easily test by clipping a jumper cable from the alt housing to the negative terminal of the battery.

It sounds to me like your alternator isn't getting turned on. Check the electrical plug(s) connection and cleanliness. Using the wiring diagram provided and a VOM, check for power and ground at all the appropriate connections.

 

[allgravey20]

Yes this what my thoughts were too. Are both wires in the plug suppose to have + voltage when the vehicle is running?

 

[koda2000]

The "A" wire should have battery voltage with the key on. The "B" wire should have around 13.6-14 volts with the engine running. The LT GRN/RED wire comes from the BATT light and should show battery voltage with the key on and the engine running. Once the engine starts the voltage regulator should break the ground connection for the BATT light, turning it off.

With your VOM, check for continuity across the mega fuse. Be sure to test where the wires connect to the fuse and not the fuse itself. The fuse may be good, but if the terminals get corroded they may not pass the current.

 

[allgravey20]

I ran new wires from the battery to the alternator and got it to turn on and charge. Will that draw enough to drain the battery if i fuse it to the battery or do i have to run it to the fuse box so its controled by the ignition?

 

[koda2000]

I ran new wires from the battery to the alternator and got it to turn on and charge. Will that draw enough to drain the battery if i fuse it to the battery or do i have to run it to the fuse box so its controled by the ignition?

Which wire is causing the problem? If it's one that's controlled by the ignition switch, then you need to have your new wire controlled the same way. An easy way to do it might be to attach the new piece of wire to the existing ends of the wire that has the break. In that case I would solder and shrink-wrap the new connections for safety and reliability.

 

[allgravey20]

Yes its the ignition wire. I guess i just dont know the best and easiest place to splice into it.

 

[koda2000]

If your VOM has a continuity test setting, you can stick sewing/straight pins into the offending wire about every 10 inches and keep testing for continuity along the wire until you find the area of the break.

You can get free wiring diagrams at the link below. Use rrcc and rebsco to login, then go to the automotive reference section and specify your make/model and year. Maybe that will help you determine where the best place to splice/repair is.

http://search.ebscohost.com/

 

[DrewSmith007]

Just went through this and other threads with a similar problem, but none of the solutions worked.

Instrument panel battery light would come on with key, then stay on when running.

Checked voltage at the battery while running, same as when off.

Checked continuity of all the power cables, both positive and ground. All had good conductivity back to the battery terminals.

Removed the battery connection from the alternator, only got about 0.5v output on the post while running.

Decided to replace the alternator at this point, no improvement. Still no charge, battery light on all the time, and no alternator output.

The problem ended up being one of the unlabeled fuses in the power distribution box is for the alternator. It was blown, I assume preventing the alternator from "turning on".

Turns out the bearings were in really bad shape on the alternator anyway...

EDIT: The alternator fuse is #16 on my '93.