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Discussion Starter #1
I'm new to the site and Nissan's I bought an 03 1.8 Sentra 5 spd that was in a rollover accident. I race dirt track and plan to race this car. The poor thing has already been through alot and someone who was helping me get the car ready cut through the wiring harness that runs along the driver side to the back. Obviously I had to reconnect some wires for the fuel pump but I didn't reconnect them all. Now my problem is my alternator isn't charging the battery and I changed the alternator and still nothing so I found that the plug that goes into the alternator from I believe the ecm has no current in either wire so now I believe it's an ecm issue however I am going to reconnect all of the wires and see if that helps. Basically I'm just looking for some advice or suggestions before I get too much time and money in it thanks in advance
 

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Nothing goes to the ECU. There are 1 connector (2 wires) and the big battery cable that's attached to the alty. The 1 big one goes to the fuesable link (100A) at the fuse box next to the battery. The 2 wire connector has 1 that goes to the cluster batt light and the other (green/black) wire goes to the fuse box as well marked "horn" as seen here: 02-06 - Relay & Fuse Diagrams

Download the FSM, under sc.pdf you should see the wiring. Is the block grounded? That's how the alty is grounded.

Check those wiring and see if they're still connected.
 

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Thanks so much I definitely took the horn fuse out but not sure if it was before or after this problem started I will definitely try to see if that helps the issue
 

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So I put the fuses back in for horn still nothing block is grounded so I'm still lost
 

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Do you have continuity between the fuse and the wire off the alternator? Have you downloaded the FSM?

 

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Discussion Starter #6
I have power from the green and black wire after I found the green and black where the harness was cut and have the fuse in but still no charge coming from the alternator it keeps telling me oops we ran into a problem trying to download it
 

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Discussion Starter #7
Is there a 1 wire alternator that I could use with minimal fabrication if not could I just make a bracket and run a Delco 1 wire and make it work
 

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I did also find some engine codes the one that worries me is U1001 because it deals with the ECM I think that is because when the car was wrecked the exhaust was torn off which includes the O2 sensor from the cat would that be another issue or part of the same issue with the alternator not charging I'm just so lost and frustrated with the car I dont want to scrap it but that's probably next before I waste any more money on it
 

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I would just pull the harness that runs from the alternator, under the radiator and into the driver side cabin(should be one large harness) and look for breaks, speaking from experience.
 

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Here are the pages off the FSM. The 1 green/black wire IS the single wire that you're looking for if you get what I mean. That is the green/black wire is the input voltage to the alternator regulator. If you have 12v there and you have a good connection to the battery with the big wire, then it should just charge it unless you have a bad battery or a bad out of the box alternator. Have you tried swapping it with the old one?

Also don't worry about the U1001 code, that's a can code for the cluster. That's a whole different issue if want to keep it codeless. With a 5sp, that's just how the RPM, coolant temp, vss, fuel level stuff is transmitted. It's all laid out on the FSM. You could try getting the fsm from www.nicoclub.com/fsm

Alty.png Alty2.png
 

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Discussion Starter #11
I will swap the other alternator when I can this weekend hopefully that will work I'll also check the fuses again but the green and black is getting power about the same as the battery is putting out
 

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Discussion Starter #12
Big thanks to you guys for the assistance I finally realized that with the gauge cluster being disconnected there is a diode in that which is what the orange wire goes to and sends power to the alternator so for right now I'm looking to get a cluster because mine got "misplaced" but I ran a wire from a fuse that I'm not using to the alternator and now it will charge but I want to send the correct voltage not just 12 volts I'm worried it will burn the alternator up if I keep sending 12 volts thanks again guys
 

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To be honest...I didn't think that diode on the diagram has anything to do with it, that's the LED on the cluster that tells you have a charging issue hence why I didn't really say anything about it.
 

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Discussion Starter #14
Yeah it kind of blew my mind but it did start charging when I hooked the wire up to the battery. Hopefully I don't have any other issues and can get the car ready to go racing here soon. I will post some pics when I get it all done. I really do appreciate the help though and I may have some more questions maybe to make it faster.
 
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