ELECTRICAL Troubles

Topics related to Lights, Radio, Stereo, Headunits, Alternators...

Moderator: volvite

User avatar
VStar650CL
Posts: 501
Joined: Wed Dec 09, 2020 6:19 pm

Re: ELECTRICAL Troubles

Postby VStar650CL » Sun Mar 06, 2022 10:05 pm

Sounds like a tree to me. Start barking.
:wink:


User avatar
Code Pathfinder
Posts: 209
Joined: Thu May 18, 2017 6:54 am
Location: Minnesota

Re: ELECTRICAL Troubles

Postby Code Pathfinder » Mon Mar 07, 2022 8:23 pm

Here is a wiring diagram for the charging system in our pathfinders from 05-12

Courtesy of https://portal-diagnostov.com/en/

Image

So let's go over it.

Your alternator has 5 main points on the system.

Earth - AKA Ground. These are the BLK wires found on the wiring harness. The Alternator also grounds through the engine block which is then grounded to the chassis.

Battery - Black/red wire. Runs from the Alternator to the fat fuse. Basically completes the circuit for the other fuses from the diagram. The black dots signifies that connection. Black Dots on an electrical diagram mean that the wires connect at that point. As we can see, The Positive cable provides power to both 140 Amp and 80 Amp relays on the positive battery fusible link.

Sensor wires - Blue, Yellow, Pink

Blue - Sensor wire to the battery. connects to fuse 30 in the relay box in the engine bay then runs to the 80A Circuit on the battery fusible link.

Yellow - Sensor wire to the Computer systems. IPDM, PDM, Etc. This yellow wire is absent on my aftermarket alternator so I will not get a reading through this. DC Power Engineering explained to me that this wire is unnecessary for my application but still must be present on the factory harness.

Pink - sensor wire to the Cluster Gauge/switched ignition source. This tells the cluster gauge what the voltage is via the Charge indicator.

User avatar
VStar650CL
Posts: 501
Joined: Wed Dec 09, 2020 6:19 pm

Re: ELECTRICAL Troubles

Postby VStar650CL » Tue Mar 08, 2022 5:31 am

Code Pathfinder wrote:
Mon Mar 07, 2022 8:23 pm
Earth - AKA Ground. These are the BLK wires found on the wiring harness. The Alternator also grounds through the engine block which is then grounded to the chassis.

Battery - Black/red wire. Runs from the Alternator to the fat fuse. Basically completes the circuit for the other fuses from the diagram. The black dots signifies that connection. Black Dots on an electrical diagram mean that the wires connect at that point. As we can see, The Positive cable provides power to both 140 Amp and 80 Amp relays on the positive battery fusible link.

Sensor wires - Blue, Yellow, Pink

Blue - Sensor wire to the battery. connects to fuse 30 in the relay box in the engine bay then runs to the 80A Circuit on the battery fusible link.

Yellow - Sensor wire to the Computer systems. IPDM, PDM, Etc. This yellow wire is absent on my aftermarket alternator so I will not get a reading through this. DC Power Engineering explained to me that this wire is unnecessary for my application but still must be present on the factory harness.

Pink - sensor wire to the Cluster Gauge/switched ignition source. This tells the cluster gauge what the voltage is via the Charge indicator.
That's mostly correct, except YEL isn't a sensor. It's a PWM control line for the variable charge rate system. See SC-29 in the FSM for an '05. It's a common setup on many Nissans, and when it fails it usually causes undercharging for people who make a lot of short trips. It's rare for it to cause overcharging, but you can find out by simply unpinning the wire at either end (the IPDM end is generally easier). When disconnected, the alternator will run as "fixed regulation" and simply output it's rated voltage like a conventional alternator. Part of the problem with this system is crappy documentation, the FSM tells you how to check if the PWM works but not what parameters the system uses to set the charge rate. There are four devices involved, the battery Current Sensor which is read by the BCM, the system voltage which is read by the ECM, and the IPDM which runs the alternator. Nissan doesn't make clear where the charge rate decisions are coming from. If it's buried someplace in the LAN documentation, I've never found it.

User avatar
Code Pathfinder
Posts: 209
Joined: Thu May 18, 2017 6:54 am
Location: Minnesota

Re: ELECTRICAL Troubles

Postby Code Pathfinder » Tue Mar 08, 2022 12:22 pm

Thank you for the clarification Vstar.

I should show a more accurate diagram of my current setup.

Image

On my current alternator, there is not a yellow wire coming from the units pig tail harness. DC Power Engineering does not utilize the signal to the IPDM rather its regulated internally via its voltage set point.

Image


Return to “R51 Electrical”