Electrical Wiring power from trunk to front

roldy

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Jul 22, 2020
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I've posted this question before on another forum but I think the approval system is bugged as I'm still waiting for my post to be posted.

I would like to relocate the starter relay terminal to the trunk where my battery is in my 88 mustang. I have also been doing a fresh installation of all the interior wiring. I've been doing some research and put together a graphic of what I think I need the routing to look like. I have a removable key cut off switch that will be mounted under the dash somewhere for an additional theft deterrent. The starter is a mini starter that is already installed on the engine. Is there anything that I'm missing and should include? Does my routing look good and safe?

wiring.png
 
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jrichker

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Rear mounted battery wiring recommendations

For a battery cut off switch, see https://www.moroso.com/catalog/pro...rnator-disconnect-switch74108/category/3114/
is the switch
https://www.moroso.com/pub/media/instructions/74108_instweb.pdf is the installation instructions.

Switch picture...
Morso battery cutoff switch.JPG

Use the super duty switch and the following tech note to wire it and you will be good to go.

Use the Moroso plan for the alternator wiring and you risk a fire. The 10 gauge wire they recommend is even less adequate that the stock Mustang wiring.

There is a solution, but it will require about 40' of 18 gauge green wire.

Wire the battery to the two 1/2" posts as shown in the diagram.

The alternator requires a different approach. On the small alternator plug there is a green wire. It is the sense lead that turns the regulator on when the ignition switch is in the run position. Cut the green wire and solder the 40' of green wire between the two pieces. Use some heat shrink to cover the splices. See http://fordfuelinjection.com/?p=7 for some excellent help on soldering & using heat shrink tubing.

Run the green wire back to the Moroso switch and cut off the excess wire. Try to run the green wire inside the car and protect it from getting cut or chaffed. Crimp a 18 gauge ring terminal (red is 18 gauge color code for the crimp on terminals) on each wire. Bolt one ring terminal to each of the 3/16" studs. Do not add the jumper between the 1/2" stud and the 3/16" stud as shown it the
Moroso diagram.

How it works:
The green wire is the ignition on sense feed to the regulator. It supplies a turn on signal to the regulator when the ignition switch is in the Run position. Turn the Moroso switch to off, and the sense voltage goes away, the voltage regulator shuts off and the alternator quits making power.

The fuse & wiring in the following diagram are for a 3G alternator. The stock alternator uses a dark green fuse link wire that connects to 2 black/orange wires. Always leave them connected to the starter solenoid even if you have a 3G alternator.

attachments\589892


Rear mounted battery ground wiring. Follow this plan and you will have zero ground problems.

One 1 gauge or 1/0 gauge wire from battery negative post to a clean shiny spot on the chassis near the battery. Use a 5/16” bolt and bolt it down to make the rear ground. Use a 1 gauge or 1/0 gauge wire from the rear ground bolt to a clean shiny spot on the block.

One 4 gauge wire from the block where you connected the battery ground wire to the chassis ground where the battery was mounted up front. Use a 5/16” bolt and bolt down the 4 gauge engine to chassis ground, make sure that it the metal around the bolt is clean & shiny. This is the alternator power ground.


attachments\48657


The computer has a dedicated power ground wire with a cylindrical quick connect (about 2 ½”long by 1” diameter. It comes out of the wiring harness near the ignition coil & starter solenoid (or relay). Be sure to bolt it to the chassis ground in the same place as you bolted the alternator power ground. This is an absolute don’t overlook it item for EFI cars
Note: The quick disconnect may have fallen victim to damage or removal by a previous owner. However, it is still of utmost importance that the black/green wires have a high quality ground..

Picture courtesy timewarped1972
653516-6625680e1bef18543fb94c300ca7bf08.jpg


Crimp or even better, solder the lugs on the all the wire. The local auto stereo shop will have them if the auto parts store doesn't. Use some heat shrink tubing to cover the lugs and make things look nice.
 

Attachments

  • Common chassis ground point.JPG
    Common chassis ground point.JPG
    78.2 KB · Views: 11
Last edited:

roldy

New Member
Jul 22, 2020
24
0
1
Rear mounted battery wiring recommendations

For a battery cut off switch
, see https://www.moroso.com/catalog/product/view/id/8487/s/battery-and-alternator-disconnect-switch74108/category/3114/
is the switch
https://www.moroso.com/pub/media/instructions/74108_instweb.pdf is the installation instructions.

Switch picture...
Morso battery cutoff switch.JPG

Use the super duty switch and the following tech note to wire it and you will be good to go.

Use the Moroso plan for the alternator wiring and you risk a fire. The 10 gauge wire they recommend is even less adequate that the stock Mustang wiring.

There is a solution, but it will require about 40' of 18 gauge green wire.

Wire the battery to the two 1/2" posts as shown in the diagram.

The alternator requires a different approach. On the small alternator plug there is a green wire. It is the sense lead that turns the regulator on when the ignition switch is in the run position. Cut the green wire and solder the 40' of green wire between the two pieces. Use some heat shrink to cover the splices. See http://fordfuelinjection.com/?p=7 for some excellent help on soldering & using heat shrink tubing.

Run the green wire back to the Moroso switch and cut off the excess wire. Try to run the green wire inside the car and protect it from getting cut or chaffed. Crimp a 18 gauge ring terminal (red is 18 gauge color code for the crimp on terminals) on each wire. Bolt one ring terminal to each of the 3/16" studs. Do not add the jumper between the 1/2" stud and the 3/16" stud as shown it the
Moroso diagram.

How it works:
The green wire is the ignition on sense feed to the regulator. It supplies a turn on signal to the regulator when the ignition switch is in the Run position. Turn the Moroso switch to off, and the sense voltage goes away, the voltage regulator shuts off and the alternator quits making power.

The fuse & wiring in the following diagram are for a 3G alternator. The stock alternator uses a dark green fuse link wire that connects to 2 black/orange wires. Always leave them connected to the starter solenoid even if you have a 3G alternator.

attachments\589892



Rear mounted battery ground wiring. Follow this plan and you will have zero
ground problems.


One 1 gauge or 1/0 gauge wire from battery negative post to a clean shiny spot on the chassis near the battery. Use a 5/16” bolt and bolt it down to make the rear ground. Use a 1 gauge or 1/0 gauge wire from the rear ground bolt to a clean shiny spot on the block.

the lugs and make things look nice.
I meant to include the PDF page from the wiring kit that had instructions for wiring the power. I did a little merging of the wiring kit with relocation wiring diagrams and that's how I came up with my diagram. When I get serious about drag racing I will install the Moroso cutoff switch but right now I just want an added power cutoff hidden with a removable key. The base wiring diagram I used was the solenoid relocation diagram.
 

Attachments

  • power wiring.png
    power wiring.png
    131.5 KB · Views: 15
  • solenoid relocation.png
    solenoid relocation.png
    131.5 KB · Views: 16