charging problem?

[Alabama Mike]

ok, I know I have read about this on here somewhere before, but can't seem to find it right now. my M1009, the Gen 2 light glows slightly, and ever so often I have to put the charger on the back battery. I have check output on both alternators, left side 14.8, right side 14.6, should be more than enough to keep things charged, So anybody know what my problem might be? I replaced both batteries this past summer so I would think there good.

 

[doghead]

Have your battery tested again.

 

[Warthog]

Before any electrical testing make sure your batteries are fully charged and load tested.

I have seen new batteries that where DOA on the shelf. Never assume. Verify.

What is the voltage reading at the battery? You may have a bad connection that is not allowing the alternator to reach the battery.

 

[Alabama Mike]

Before any electrical testing make sure your batteries are fully charged and load tested.

I have seen new batteries that where DOA on the shelf. Never assume. Verify.

What is the voltage reading at the battery? You may have a bad connection that is not allowing the alternator to reach the battery.

Not know exactly how the 24 volt system works, can the voltage be checked at each Battery? I know that might sound like a stupid question. Last time it did this I charged the battery and had it load tested and it tested good. I have the low battery on the charger now, and the other tested good this time around too, as soon as battery #2 has a good charge I'll test it as well.

 

[Warthog]

You can check each battery by itself. Just attach the meter to the leads to the individual terminals.

This will give you the output of each alternator.

read the stickies to get a better understanding of how the system works.

 

[markg]

You can also swap the batteries and see if the light problem follows after you get the rear charged. it might help eliminate number 2 alternator.

 

[Alabama Mike]

Ok, got 2nd battery charged and did a load test with a VAT 40, battery tested well, I'll check each battery voltage tomorrow sometime, were starting to get bad weather here, seems we just aren't made for snow down here in Alabama!!! I'm reading thur the stickies now, I somewhat understand how the system operates, also my volt meter is not working, it never has so I was thinking it was just broke, while I have gotten that far in my reading does the volt meter not work mean anything (I might be answering that question myself as I get further in to the stickies)

 

[Warthog]

The non-working voltmeter could mean there is an issue with the GEN2 charging system. Check the very bottom fuse. If it is bad the meter won't work.

 

[Alabama Mike]

OK checked batteries today, front battery is showing 14.6, rear battery is showing 12.7, seems I'm loosing juice between the pass side alt and the rear battery, I did recheck both alts, drivers side 14.8 passenger side 14.6, I checked the bottom fuse, its was not blown, I cleaned it and put it back in place, any ideas?

 

[doghead]

I would rebuild the alt in question.

They can charge and have a draw.

 

[Alabama Mike]

I would rebuild the alt in question.

They can charge and have a draw.

I don't quite understand what your saying, how can it charge and draw at the same time?

 

[cpf240]

Perhaps a bad diode trio. It can charge while the engine is running, but then draw through the a bad diode when not running. Put an ammeter on the output lead and see if it is drawing when the engine is not running.

 

[markg]

If you have 14.6 v at the gen 2 and you have just battery voltage (12.7) at the back battery then you have a bad cable connection at the battery post or the connection on the back of the alternator is loose.

 

[Warthog]

Or a blown fusible link from the GEN2 at the 24v buss bar

 

[Alabama Mike]

I found a wiring diagram in the stickies, I'm gonna start chasing wires tomorrow, hopefully I'll get to the bottom of it, I did read something about 2 differant bulbs in gen1 and gen 2 lights, if someone had put the same bulb in both would that make the gen2 light a very dim light?

 

[markg]

I found a wiring diagram in the stickies, I'm gonna start chasing wires tomorrow, hopefully I'll get to the bottom of it, I did read something about 2 differant bulbs in gen1 and gen 2 lights, if someone had put the same bulb in both would that make the gen2 light a very dim light?

Bulbs are the same, even when they are bad alternators can still energize. your previous post says they are both already charging. look to the connections. you will find it!!. thanks. mark

 

[cpf240]

Bulbs are the same, even when they are bad alternators can still energize. your previous post says they are both already charging. look to the connections. you will find it!!. thanks. mark

No, the bulbs for GEN1 and GEN2 are different...

 

[markg]

No, the bulbs for GEN1 and GEN2 are different...

ok, so educate me. how are they different?

 

[Warthog]

One is a 194 and the other is a 168. Different wattages for the different voltages. I'll have to look at my notes to tell you which one is which.

The parts manual has them listed.

 

[rtk]

More than likely you have a bad Diode in your alternator . It is a common problem with the GM alternators , bottom line , you need a rebuild .