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The Power Train Control Module controls the field by duty cycling a ground on the control wire. The other field wire is fed by the Auto Shut Down Relay so it will only be powered when the engine is running. Test the charging system amperage output. It should be over 75 amps. If not, then replace the alternator. Monitor the field positive circuit for charging system voltage, once the engine is running, on the Dark Green/Orange wire. Use a scope to watch for drop-outs of voltage. Repair the wiring as needed. Verify there is nothing wired in to the Dark Green wire between the alternator and the PCM. Remove anything that is hooked to this circuit. Monitor the field control circuit (Dark Green) wire to the PCM. The voltage should be switching from battery voltage down to ground when viewed on a scope. Using a voltmeter will result in an average reading and not work for this test. So at the alternator 3 wires should have power and 1 wire should pulsate ground off/on, here is a wire diagram to help with tests. Let me know if you have quwestions, thanks.
ok i see the three wires. the black with orange stripe,,,the blue,,,, and then the main one that goes to battery. now there is no voltage at all comeing out of the main one to battery,, what kinda voltage should i expect on the blue and the bl?ornage wires?
The main one going to the battery should at least have battery voltage, if not follow wire and try to locate fusible link on wire. The blue one is pulsated ground off/on to control charging and the black/orange one should have voltage when vehicle is running. Let me know what they are, thanks.
i had 12 volts on the main wire while running, i beleive the black wire and the blue wire were around 11.7
i may have been wrong about the blue but we definately had 11.7 volts to main wire and to black/orange wire with engine running. but shouldnt it be puting out 14 volts or better? would 11.7 volts just be reading the battery?
are you saying to jump blue wire to ground?
Basically but not directly to ground, you dont want to burn up alternator....But if you tap ground off/on on the blue wire it shoudl charge. Let me know, thanks.
ok. i did just like you said and sure enough, as soon as i touch it to ground , she shot right up to 14 volts. so its definatley the pcm?
and if i get a used on from juk yard do they need to be flashed on this particular model?
First make sure that wire between alternator and pcm is good....If so, then its the pcm....I think you should be ok with a used pcm without having to flash. Let me know if you have questions, thanks.
dan. you are the man. im pretty sure thats what it is too. so im gonna accept your answer. theres an extra big tip in for ya if ya dont mind one more question about another car? ihave 00 taurus that starts and runs for about 2 seconds then dies. the security light is flashing.
hey dan, on the sebring... i changed pcm. no luck. still not charging
hey dan. not tryin to be a pest, but have you heard anything yet.?
yes. i tried that. it was one of the first things i tried. what are the odds of the new pcm being bad? i mean as soon as i shorted out the blue wire i had a full charge???
are there any other components to the chargiing system that i am missing?
To me it seems like the new pcm may be bad since there really isnt that much involved in the system but I hate replacing brand new parts, especially pcm's......But if all the other wiring is good I'd say replace again.....You could also make sure the power/grounds on the pcm are good. Let me know how it goes, thanks.
which ones are the power/ grounds?
hey dan. i had another pcm shipped from a place in florida but it gave me a no start situation so i am sending it back. they asked me to ship them MY pcm since it starts the car they said they can fix the charging problem in it. but b4 i send it to em i wanted to know more about the possibility of the power/ ground wires. which ones are they and whats the best way to test em? please help. ive had this ladys car 2 weeks now. she's getting angry and im getting desperate. thanks
Considering it charges when you ground the wire going to the pcm that shows that all of the other wires are good going to the alternator. Here is a connector diagram so you can test pcm power/grounds.
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i'll check again and get back to ya. been a week since i had it up in the air
what is ASD and were is it?
Here is a picture but if this was the probelm other things would be effected to but it may be wire between relay and alternator.
ok i found relay. any thing secific i can do to test the socket and the relay?
using a test light with key off. pin 46 has power. do i test it with volt meter?
what about the ASD relay. should i look into that?
ok with meter and engine running i push in on plastic housing of the pigtail that plugs into the back of the alternator and engine starts charging and when i relaes it it stops charging. im going to change pigtail but i don think thats it. i think its actually the female socket on the alternator itself thats bad
ok. i changed the alternator and we are good. tell all you reinds and family LOL. i even took old alternator to have it tested and it still tests good. its just that socket that is bad
thankss for all your help and patience.
hey dan i need help with an electrical problem (dome lights) on a 96 cherokee your the man with all the electrical answers so if you can help me i'll open another question to you. only reason i went through this post is cuz i can never catch you online. this way when you respond to this. i'll get a text message letting me know you on. thanks
i replaced the drivers door on this 1996 cherokee with a used door off a 93. everything was identical. and i used ALL the parts from the old door.but for some reason. ever since i changed the door. the interior lights will not go off unlees the key is in the on position. i know all the switch at the doors work because the lights go on and off when i open and close all 5 doors one at a time. but only if the key is on. as soon as i turn the key off. BOOM all the dome & door lights come on. now i wanna make sure you get paid. so if you thnk you can helpme lemme know and i'll repost this as a new question
touch what cables together? the pos and neg battery cables?