Archived not charging

[LTaylor]

I'm posting here because the truck is not currently working, if it belongs somewhere else please forgive me and feel free to move it.



2001. 5 4x4, 6sp, ~270,000 miles.



The truck is not charging the batteries. (I barely got home last night in the rain... using running lights only) Batteries were dead when I arrived and would not start the truck after turning it off. Now I've recharged them overnight it will start but not charge.



Symptoms when I lost the voltage gauge were this:

Driving at night, the check engine gauges light comes on, and the voltage gauge is slowing dropping to around 8 volts then dropped totally to zero. I turned the key off and then on and the gauge came back... but within a minute slowly back down to 8V again, the check gauges light comes on and the voltage gauge drops to zero. The other gauges: speed/tach/temp/etc. are all still working.



I've done a bit of reading here today and took the alternator to NAPA & Autozone and had it tested... it failed both times. I bought an Autolight Pro-tech remanufactured alternator with a lifetime warranty (any idea as to the quality of these?) and then had it tested... well two of them failed also. Their explaination of why is that because this alternator is externally regulated it is impossible to check on their machine. (what do you think about that?) So I went ahead and brought my core back home.



Before pulling the alternator, I started the truck after pulling the alternator leads and the small plug has two pins... . checking voltage between them and ground have less than one volt on one and a variable reading on the other (4V through 9V). The wire that goes over the large stud produced nearly 13V (I assume that that is connected to the (+) side of the battery?



I know that my throttle positioning gadget (variable resistor, or sensor forget what it's called) is wearing out... I've adjusted it once about 30k ago as per the instructions here on TDR. I recently two weeks ago lost all gauges and power (truck still idled) and after turned off sitting a bit it worked again. Heavy throttle application will produce a missing sensation (I thought maybe there was water at first... but now am guessing the throttle positioning sensor needs replaced.



That is unless it's the PCM. (which also houses the external voltage regulator right?)



I'm reluctant to simply install the new alternator for fear it may be something else and money is a bit tight right now (I've got to do a wheel bearing and brakes).



So what do you think? Is there a way to rule out the PCM? If I could rule out the PCM I'd just install the new alternator... . a customer at Schucks where I got it was very down on schucks quality (and the new one DID fail the test, that is it failed IF you can test it reliably on a machine out of the truck) ... . So if I'm going to slip a new alternator in might rather find a better quality unit...



I need some guidance on how to proceed please.

 

[John - K5AWO]

Have you measured the output voltage of the oem alternator at the output post?

My truck blew the 130 amp fuse between the alternator and the batteries a while back. (I shorted the alt post to ground, oops) The fuse didn't blow right away, but it was damaged enough that it failed a few months later.

The symptoms were similar to yours, and I bought a new alternator which did not fix things. (truck was in California w/another driver) I finally got the driver to put a voltmeter on the alternator postive post and he measured 30+ volts with nearly dead batteries!! A new fuse fixed it right up. Now I have a spare alternator in the toolbox ... ...

 

[Missouri Mule]

To test new alternator you can hook a remote voltage regulator to it. You can do this while on the truck by-passing the EVR in the PCM.



But they used to test alternators all the time on the bench that had external voltage regulators.



I believe internal regulators (inside of alternator) came out in the 80's sometime. (When they went bad the - and + poles would change. )

 

[bmoeller]

The PCM regulates the voltage on these trucks. If the 120A fuse is good, and the alt is good, check all of the grounds (including the PCM).

Have the batteries load tested and clean all of the battery connections.

I blew my big fuse the same way John did. It blew right away, though.

 

[B.G. Smith]

At 270,000 miles I would suspect the brushes are worn out in the alternator. Testing an alternator that is controlled externally is simpler that testing one with internal control. You are correct in the id of the big terminal, it goes to the batteries. The alternator produces voltage by coils passing through a magnetic field. Actually in the alternator the coils are stationary and the magnetic fields rotate. To make the rotor magnetic, voltage from the battery is introduced through the brushes to the slip rings of the rotor and into the wiring. The higher the voltage introduced, the greater the magnetism and the higher the output of the alternator. I have absolutely no experience with the alternators on our trucks but I would venture a guess that the two small wires go to the slip rings. If you checked continuity across them (the ones on the alternator) while disconnected from the truck there should be failry low restence but I have no idea what. Hope I haven't thouroughly confused you. bg

 

[FourBarR]

No indication on your post that you checked for codes. Ignition switch on ,off,on off, on, off leave on after 3rd. time read codes on odometer window. dont start the engine ,just turn the key on off. Post the codes if there are any. Hope this helps.

 

[LTaylor]

Okay gang,
Thank you for all the responses so far. You're the best!

I'm still down but truly haven't applied myself today to fixing it... :-( had a bunch of meetings and church.

Anyway, I DID pull the codes: Not sure what they mean.
first batch: 1693.
second batch: 0230.

I also put the old alternator back on and I also have a new serpentine belt... the old one was cracked and had way over 100k miles! Maybe the pulley was slipping?

Battery terminals are cleaned and tight.

Also I tried unsuccessfully to find the 120amp fuses between the alternator and the battery. Where are they, are they on the firewall?

I did check the brushes in the alternator, and they appeared to still be touching... looked to be about 3/8 or 1/2 inch long... but worn of course. The other electronics around the brushes... the diodes(?) had no discoloration or burning that I cold tell except dust.

In the morning I'll check voltage between the output on the alternator and the battery, check grounds (if I can find them) and have the batteries load tested. (the batteries WILL start the truck... that's a pretty big load I'd think... is that enough?)

So goodnight, and I'll report back tomorrow.
Thanks

 

[Missouri Mule]

No. 1 the fuse you are looking for is in the PDC. PDC is under hood near driver's side fender.

No. 2 code 230 transfer pump circuit out of range. Does not sound like that one helps you out. 1693 means a code has been detected in ecm/pcm.

 

[Breed]

My truck had the same symptoms and it was the fuse, somehow I shorted it while changing the Oil filter, hope this helps a little.

 

[LTaylor]

Okay here is the newest update.

I have only fuse I've been able to find in the PDC is a 140 amp fuse. I tested "0" zero ohms across it when taken out. I've put it back in.

I can't seem to find the 120 amp fuse between the battery and the alternator... . is the 140A it? (I thought the grid heaters were the 140A fuse)

The original alternator today tested 24. 5 volts at the output when the output wire was removed and the truck running. (the two prong plug was still in there).

I took the alternator I bought to NAPA (the one that failed at Autozone) and it passed. My original alternator failed at the NAPA on Saturday.

So as soon as I can rule out the fuse issue I'm thinking that it might be the alternator... then I'll install it.

Can you help me find the fuse?
Any other ideas?
Dang I havent' checked the grounds yet... . how do I do that?

Thank you SO much!

 

[B.G. Smith]

The alternatoer fuse (generator) will be located where the 06 ga. red wire enters the PDC. It will be a strip of fusable metal mounted with two screws/bolts. On the 99 I had I believe you could see it when you removed the cover from the PDC but on the one I have now it is not visible, looks lie I would have to remove a second cover on the pdc which has 4 screws holding it in place. I don't know how the 01 is set up? bg

 

[LTaylor]

Oh, I've got some good news... .

It appears to be charging. I had removed the 140A fulse in the PDC thinking that would disable the grid heaters... I did that on Sat. after having the problem on Fri. night. Anyway as we've been fiddling with it I put it back in and drove it home from work after charging the battery today while at work.

Anyway it worked, it charged! A miracle I think, (I've been praying really hard).
The only thing different from when it stopped charging is that I put a new gatorback belt on it... replacing the one with close to 140,000 miles on it. Could that have been it? The belt was slipping under load?

Now I still have a few questions... . why is my alternator putting out 24. 5 V? and I still have a check engine light (does it just take awhile to have that clear?). I need to go pull codes again.

I believe that on the dual battery HD 6sp, H. O. engines, towing special, etc. 2001 that fuse might actually BE 140A. I'll continue to look into that... along with checking the ground points.

Thank you all!
And if you have any other thoughts especially about what appears to be working now and my additional questions please chime in.

 

[LTaylor]

I guess I'm back to the intermittent charging. Tonight on the way home from ballroom dance lessons it stopped charging. I was on the freeway so I quick cycled the key and it started charging again.



So I'm still thinking it has to be that fuse (even though it looks and tests fine), the grounds, the alternator, or the PCM... in that order?



The batteries are in parallel right? So shouldn't they be charging at 12-14V not 24. 5V?

 

[B.G. Smith]

If the 140 amp fuse goes, it's not going to resume working. It could be the PCM but I would change the brushes in the alternator first. Yes the batteries are parelell, 12 volts, the charging rate should be about 14. 5 volts, don't depend on the volt meter in the dash to be real accurate. bg

 

[San Felipe Bob]

brushes

My brushes were gone at 220k.

When the brushes started to go it caused all kinds of electrical gremlins.

Just about every thing the PCM senses uses 13. 5 to 14. 5 volts as a baseline.

When it was acting up the voltage was all over the place.

I put in an Autozone unit.

It's still working.



SFB

 

[LTaylor]

I shorted out the 140A fuse this morning taking the alternator output wire off with the batteries still connected! (don't do that) so had to replace it anyway.



I called Husky Auto electric here in Boise, who said that to rebuild the alternator ... brushes and bearings would be about $125. The woman there felt sure my problems were coming from worn alternator.



While picking up the 140A fuse I talked to a dodge mechanic, he also felt sure that it was the alternator. One thing he told me was to never check the voltage at the output stud on the alternator, but to test it at the Power Distribution Center (PDC).



I gave up hoping it was a fuse or ground and simply installed the new alternator. And no suprises here for you forum members I'm sure... . I think it is solid and charging. (I am a little hard headed sometimes).



Thank you all for your time and for your help. You really are the best!



Now it's time to do brakes and a wheel bearing. (should I only do the L. front or both of them at the same time?)

 

[San Felipe Bob]

both

I'd do both front brakes and both wheel bearings.

Be sure to check out your front axle univesal joints too.



SFB