Running my Starter & 1 wire Alternator cables tonight....

Discussion in 'Fox 5.0 Mustang Tech' started by Busted07, Jul 11, 2007.

  1. Im going to run a positive (+) cable from the solenoid to my starter, and i had a question.

    Once i run the cable from the solenoid to my starter, can i run a cable from the starter up to the alternator? Or do i HAVE to run one from the solenoid to the alternator?

    My 1 wire alternator has 2 connections, one for a main positive cable, and a small terminal for an optional trigger wire (which ill be running off of my original chassis harness).

    But i dont know where i should get the juice for the alternator unless i either run it from the starter up, or run it from the solenoid over... and im quickly running out of room on my solenoid to add more than 1 more wire.

    Thanks in advance for any help!!!!!

  2. no you cant. the starter only recieves power when the solenoid is tripped. the hot wire from the alternator should go on the opposite side of the solenoid that the starter is hooked too. and BTW you dont send electricity to the alternator the alternator sends electricity out to the battery. it makes electricity when the belt drives it. it doesnt need it to operate. hope this helps man.....
  3. Well ****! so does that mean i need to run a cable from the alternator back to the battery then? i should know all this from how long ive been on here, and by using common sense, but i completely brain farted on this one.
  4. yep. the wire that is coming out of the back of the alternator that has ++++ on it use a similar gauge wire to run to the solenoid or to the positve cable on the battery. either place will work.

  5. I think im gonna need some more cable... yikes! thanks man!
  6. You dont happen to have a later model starter with piggyback solenoid do ya? That could circumvent this issue.

    Good call running a switch circuit on your alt. :nice:

  7. Honestly, i havent even looked at the starter yet. I bought it from a buddy of mine, and while i was in the car running the gauge lines, he came over, and put it on under the car... ill let ya know when i look at it tonight.
  8. A quick clue:
    If you have a fat cable on both fender-mounted starter solenoid terminals, chances are you have an OEM starter. If you had a piggyback solenoid on the starter, all the fat cables should be on the battery lug of the fender solenoid and there'd be a 12-14 gauge wire on the other leg of the fender-solenoid.

    Good luck bud.

  9. Ok man, i looked at it last night... it is the larger body starter, with the little "hump" thing on top. it does not have the seperate solenoid on it. It only has 1 terminal on it so i ran a cable last night from the solenoid to the starter.... now im out of room on my solenoid to hook it up :bang:
  10. You kinda lost me. If you have an OEM style starter, you're not going to be able to readily have battery power at the starter. The only cable going to the starter is only hot when you try to start the car.

    Basically a late model or mini starter would be like if you took your fender solenoid and set it on the body of your current starter. Now you would have a battery lug to connect your alternator to. But since your solenoid isnt a piggyback, and is indeed an OEM fender mount, I'd just use the fender mount solenoid. I dont see why you couldnt just run it to the battery either (if the battery is up front).

    If you need more room for crap on your starter solenoid, a power distribution stud might work for ya.

    Good luck.
  11. Thanks for the info man, im going distribution block shopping this weekend.

    My battery is mounted in the hatch, what gauge wire should i run from the alternator back to that?

    As far as the starter, i have a cable going from the fender mounted solenoid to the starter... is that not right? im guessing its not. because when i turn the master disconnect switch on to get battery power, its going to constantly feed the starter power... where should i hook it up to instead of at the solenoid? would i be better to splice that wire to a push button start switch or something so it doesnt have power all the time?
  12. the solenoid is what seperates the power

  13. How is that when i used a test light to make sure i had power at the solenoid last night, it was constant. do i have the starter cable hooked up to the wrong side or something?
  14. 1. - you shouldn't run a cable all the way from the alternator to your battery - there should already be a wire going from the solenoid to the battery, so you just need to connect the alternator to the solenoid (the same post where the positive wire for the battery is connected). And there should still be room to attach one more cable you might just have to play with it for a while.

    2. - When you say there is constant power at the solenoid - where are you testing it? Which post is the starter connected to? It shouldn't be connected to the same side as the battery.
  15. For a battery cut off switch, see
    is the switch is the installation instructions.
    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

    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 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 power
    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.


    See the following website for some help from Tmoss (diagram designer)
    & Stang&2Birds (website host) for help on 88-95 wiring Everyone should bookmark this site.

    Ignition switch wiring

    Fuel, alternator, A/C and ignition wiring

    Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs

    Vacuum diagram 89-93 Mustangs

    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.


    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 [​IMG]

    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.