Alternator wiring diagram - batter not charging?

Tiny
AFRO2
  • MEMBER
  • 1999 CADILLAC DEVILLE
The battery not charging message came on. I turned the ignition off and car will not start when I tried to turn it on again.
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Saturday, June 14th, 2008 AT 10:24 PM

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Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
Hello,

It sounds like the alternator went bad but to be sure let's jump the battery and check the alternator here are two guides to help us get started.

https://www.2carpros.com/articles/how-to-jump-start-car-battery-using-jumper-cables

and

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Check out the diagrams (Below). Please let us know what happens.
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Saturday, June 14th, 2008 AT 10:34 PM
Tiny
MYMATTHEW33
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  • 1 POST
Replace the alternator, all fixed!
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Tuesday, February 12th, 2019 AT 2:00 PM
Tiny
99CADDY
  • MEMBER
  • 1 POST
  • 1999 CADILLAC DEVILLE
  • V8
  • FWD
  • AUTOMATIC
  • 110,000 MILES
For about two months my car's computer has been showing intermittently that the battery was not charging. It would be fine for days then for a few minutes the message would come up on my screen.

It has progressed now to the point that it is on steady and today the power level must have gone down significantly as power systems started shutting down.

The battery is new as I bought it 6 weeks ago so I am guessing by these signals that the problem may be the alternator.

What am I faced with if I decide to replace the alternator myself.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
CHISPAS
  • MEMBER
  • 20 POSTS
You should check the alternator first before you replace it, most auto parts stores will do this free of charge.
Unless the car gurus at 2 Cars Pros have a different advise.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
ED ARMES
  • MECHANIC
  • 129 POSTS
Recheck the battery. The cables may not be tight enough to provide good contact.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
BUZZSAW
  • MECHANIC
  • 1,198 POSTS
It is kinda hard to do, the alt comes out the bottom of the car, and dont puncture the radiator
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
ED ARMES
  • MECHANIC
  • 129 POSTS
Assuming you have the 4.6 Engine mounted side to side.

When you get to the step of removeing the wires and ground strap, be sure you check if they are just loose. It coul eliminate alot of work.

1. Disconnect negative battery terminal.
2. Drain engine coolant.
3. Remove cooling fans and radiator.
4. Remove serpintine belt.
5. Raise the front on jack stands.
6. Remove lower splash guard.
7. Disconnect coolant outlet and inlet hoses from under side of alternator if yours has them.
"Check wiring now."
8. Remove battery cable from starter.
9. Remove ground strap and 3 upper alternator bolts.
10. Remove hose bracket.
11. Remove lower alternator bolt and drop unit out of car.

USER NOTE: You dont need to do all that! There is a small plate that you unbolt under the radiator and you have all the clearance you need. There is NOTHING hard about this. Just watch out for your radiator.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
BUZZSAW
  • MECHANIC
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Excellent addition to this thread! Please feel free to use 2CarPros anytime!
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
ED ARMES
  • MECHANIC
  • 129 POSTS
Our job is to assist a layman in the task at hand. It might take him 5 days in his spare time. He is certainly not getting paid to work on his own vehicle.

It is your job to give as complete instruction as possible for the successful completion of the repair.

Given the information we provide, the "client " can make up his own mind wether to repair it himself or pay "you" to do it.

Our job is to give insight and lots of detail. That is what you signed on and agreed to as a moderator so just do it.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
LEOKARTXIV
  • MEMBER
  • 1 POST
  • 1999 CADILLAC DEVILLE
Electrical problem V8 Front Wheel Drive Automatic 140000 miles

I have a 99 Cadillac Deville and I am having some charging system issues. This all started right after I had the Ignition Cylinder replaced as I had a theft system light come on and I was told that one of the wires to the cylinder had broke and was causing this prompt. Anyway after that I was driving the car and the theft light came on again for a second then the traction control light came on. I shut the car off when I got to where I was going and everything was fine. A few days later it happened again but this time I noticed that I was having difficulty starting the car. I checked the battery and it was 3 yrs old so I replaced it. I drove it around for a few minutes and the theft light came back on the dash lights started flashing and the volt guage on the car showed 11.7 volts. I then figured it was the alternator or a ground. I replaced the alternator and I have checked and cleaned all the grounds. Now when I start the car it starts out at around 14 volts but the longer I drive it, it starts dropping off. And as soon as it gets down to 12.3 volts the dash lights start going off again. I drove it around a little more and the voltage came back up to around 13.6 volts. I am at a loss for what else to check any help will be apprecieated thanks.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
BUZZSAW
  • MECHANIC
  • 1,198 POSTS
It sounds like you have an alternator diode that is out.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
STEVE W.
  • MECHANIC
  • 12,883 POSTS
Sounds like you have a very large parasitic draw. If this only occurred after the ignition cylinder was replaced I would start with a visual inspection of the wiring harness and see if it is pinched or shorted under the dash where the work was done.
If the battery itself was disconnected during the repair it is also possible that there is a bad connection there and the voltage drop is due to a bad cable. GM cables are bad for corroding inside the housings for the battery terminals.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
ED ARMES
  • MECHANIC
  • 129 POSTS
If you truly cared about the client then your first and only response should have been " I have an easier way to do this" and then told him how and not let your ego out weigh your knowledge!
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
CHISPAS
  • MEMBER
  • 20 POSTS
Well said Ed.
I'm not a mechanic just a regular Joe, but if something worked for me in a particular problem I'm more than happy to share it. That's what this forum is all about.
I posted a simple question about my trany cooling lines about 2 months ago so far no answer.
I sure hope the Tech's in this forum go back to do what they pledge to do and leave the ego trips at home.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
MUNDENJA
  • MEMBER
  • 2 POSTS
  • 1999 CADILLAC DEVILLE
  • V8
  • 2WD
  • AUTOMATIC
  • 19,900 MILES
You answered my question to check out the above, but seems no one knows how to check them. Right now we simply unplug the blower when we stop, and plug it back in. This tells me you are probably right, everyone want to change out the module, no one seems to know how to check the relays or sensor. Do you know someone that would not charge an arm and leg to check out.

How much should it cost for us to get this fixed?
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
ED ARMES
  • MECHANIC
  • 129 POSTS
Thank you for your support of me in this matter. I shall always be in support of the regular Joe wether I am paid or not. I will see if I can find your question and see if I can help.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
  • 16,542 POSTS
Hello

not really sure which relay you're talking about, i'm guessing the blower motor relay? follow the link below to learn how to test an electrical relay..

https://www.2carpros.com/how_to/how_do_i_check_a_relay.htm
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
CHISPAS
  • MEMBER
  • 20 POSTS
Back to the original question.
Is it an easier way to replace the alternator other than the one Ed suggested?
Does the Caddy book shows you how or only quote's how long the dealer take's to do the job.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
BUZZSAW
  • MECHANIC
  • 1,198 POSTS
It pays an hr to 2, disconnect the battery, jack the car up in the air, put jack stands under the driver and pass doors, you need to drop the craddle in the front, remove the wires to the blower motor, dropping the frt of the craddle will pull it apart, remove the plastic splash guard and then with a jack put it under the craddle, remove the 2 frt craddle bolts and lower the craddle, it wont go far, but enough. Remove the fan relays this is where the alt will come out and remove the small plate

its much easier with a lift
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)
Tiny
CHISPAS
  • MEMBER
  • 20 POSTS
Thank you.
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Tuesday, February 12th, 2019 AT 2:01 PM (Merged)

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