[FIXED] 05 jeep liberty 3.7 charging system not charging.

God bless you my brothers and sisters.
I have a question is the voltage regulator inside the alternator? Does the pcm only control pulse to the regulator? The control wire being 19 on the PCM what does GEN.SRC mean.
Thank you for your help.

Pretty sure it's in the ECM.

Open the first file on this link. It will explain the charging system and how to test it www.remyautomotive.com/resource/Technical-Bulletins

God bless you my brothers and sisters.
Thank you Bruce.oliver for your respond , i did as the pdf said and it did not charge it just kept blowing the fuse.

God bless you my brothers and sisters.
I checked for voltage on the green wire and with it plugged in I get 0 volts unplugged batt. voltage is this what I should get?

God bless you my brothers and sisters.
So with the scanner I activated the generator field and i heard the alt. click does this mean that the pcm is good?

bruce.oliver wrote: Open the first file on this link. It will explain the charging system and how to test it www.remyautomotive.com/resource/Technical-Bulletins

Nice. Pretty sure this is what they're calling a 'Dual Field B' system. PCM switches power to the field coil in the alternator, and the other side is permanently grounded.

I checked for voltage on the green wire and with it plugged in I get 0 volts unplugged batt. voltage is this what I should get?

Which green wire? Or, did you mean the brown/dark green wire? The 0V plugged in doesn't sound good. With the engine running and the alt plugged in, that wire should read something.

Thank you Bruce.oliver for your respond , i did as the pdf said and it did not charge it just kept blowing the fuse.

So you grounded one field terminal and applied B+ to the other? If it popped the fuse, that'd suggest a shorted field coil. What rating of fuse did you use?

Monde wrote: Tyler, 0 v at the brown/dark green wire could be the pcm trying to protect itself from something wrong it senses in the alternator. Don't you think? I am only saying this because he has battery voltage with the connector unplugged suggesting no short to voltage or open.

It could be? I'm honestly not sure what kind of protection strategies this PCM might use on this output. I wanted to clarify with gilbert about his manual field test (with the jumper wire), 'cause that strongly suggests a shorted alternator.

Maybe the next step would be to connect a test light to B- and probe the brown/dark green wire? That'd show the PCM a known good load. If it pulses, then SOMETHING is working. :lol:

God bless you my brothers and sisters.
Hey Tyler my bad it is the brn/dk grn wire and yes with truck running no voltage with it plugged in. If i unplug it i get batt. voltage as for the test from the I put one wire to ground and the other to batt. . I did wait until after I started the truck before putting it to batt. poss. I used a red 10 amp fuse. How can I test the field coil?
Thank you brothers for your help.

God bless you my brothers and sisters.
Yes Sr. I do have batt. voltage at the brn/red wire coming from the batt.. It's at the brn/drk grn wire that i have no power with engine on and plugged in. If i unplug it I have batt. voltage at the harness side , grounds are good.

God bless you my brothers and sisters.
Tyler so you are saying to put batt. neg to the brn/grn with my test light. Engine on and should it be plugged in or unplugged ?

God bless you my brothers and sisters.
Tyler so you are saying to put batt. neg to the brn/grn with my test light.
Engine on test light on batt. neg. Plug in i get nothing. Plug disconnected light on.

God bless you my brothers and sisters.
Thank you all for your help the liberty is fixed it had a short in the rotor. I got that fixed and the alt. is charging no damage to the pcm thank God .

P.S Why can't I edit the topic to fixed?

gilbert wrote: God bless you my brothers and sisters.
Thank you all for your help the liberty is fixed it had a short in the rotor. I got that fixed and the alt. is charging no damage to the pcm thank God.

Great to hear, sir! Monde called it, too - the PCM sensed the short and protected the driver when connected to the alternator. I wonder how a test light connected across the field connector would have behaved? WIth a key cycle in there to let the PCM reset.

P.S Why can't I edit the topic to fixed?

We're working on that. According to the forum settings, you should be able to, but it still doesn't work. Sorry about that! I'll edit the [FIXED] in.

According to the forum settings, you should be able to, but it still doesn't work.

Connect a test light to the "Action" button on your screen, then probe a username on your screen. If the test light doesn't light, then you know the forum settings are shorted. :evil:

God bless you my brother's and sister's.
Well Bruce.Oliver link me to a way to test the alternator to see if it was the alternator or the PCM. That is where I started and found that I kept popping the fuse on the test wire. Then Tyler pops in and says that there is a short in the coill field so I took it apart and found that I had continuity from the slip ring through out the hole rotor.