Power completely dead
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Cross-Country
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Power completely dead
On my 1986 F250 7.5 I changed out my alternator to an 120 amp single wire type. Now I have absolutely no power ,ignition, lights nothing. Would not using the original alternator wire harness have anything to do with the problem and if so any ideas how to solve it.
Thanks
Thanks
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Joined: Jan 2001
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From: Virginia
Yes, the original alternator harness feeds the truck's electrical also. I would just install the old alternator wiring back in place. On the alternator end just cut and tape up what you don't need. Make sure you hook the starter relay end of the old harness back up. I believe that is where your problem is.
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Cross-Country
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Harness
First of all thank you for your help.When I got the truck it had the one wire alternator installed but not hooked up. After I figure what wires I use, I am assuming they hook directly to the S post on the solinoid. Here are a few photos of what I'm working with.
The cluster with the plug I assume is the alternator wires. The single red wire with the small plug I believe goes to the
post on the solinoid also.
Am I making sense
The cluster with the plug I assume is the alternator wires. The single red wire with the small plug I believe goes to the
post on the solinoid also.
Am I making sense
Moderator
Joined: Jan 2001
Posts: 56,993
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From: Virginia
There is only one wire that hooks to the "S" terminal of the solenoid. It's a red/blue wire and comes from the neutral safety switch if you have a automatic. That triggers the solenoid which makes the starter go.
Any hot wires you find you need will hook to the large bolt terminal on the solenoid that goes to the battery +.
Any hot wires you find you need will hook to the large bolt terminal on the solenoid that goes to the battery +.
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Cross-Country
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Alternator
I hate to beat a dead horse I'm lost on this. I initially was going to install a one wire alternator on my 1886 F250 460 but I changed my mine and I want to go with stock one instead . Now my problem is this. When I got the truck it had no alternator or harness. There is a harness with a round plug with 4 wires going into the plug and 4 male connectors inside , up by the passenger fender well. I am assuming that's the power and alternator plug. I can't find a harness that plugs into it and runs to the alternator. I checked on line., auto supply etc. Does anyone know the product number or where I can get one. Also does anyone know the product number for the proper alternator. Any help I would be appreciated.
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From: Virginia
I don't think you are going to find that harness new, only used from the junkyard. The junkyard would be your best bet, and give you a visual also of how things go together. No matter what engine they were all mostly the same. Even year to year they were mostly the same.
If you can't find anything you will have to hook it up one wire at a time. We were really getting into this with someone else's post the other day, and I had my head wrapped around it, but I would have to go back and study the diagrams again. If you can take a picture of that 4 wire connector, and try to show what colors go to the connector, I think we can get it wired up if you go get some spools of wire. Make sure one of the spools has 10 guage wire, the rest can be 14 gauge.
If you can't find anything you will have to hook it up one wire at a time. We were really getting into this with someone else's post the other day, and I had my head wrapped around it, but I would have to go back and study the diagrams again. If you can take a picture of that 4 wire connector, and try to show what colors go to the connector, I think we can get it wired up if you go get some spools of wire. Make sure one of the spools has 10 guage wire, the rest can be 14 gauge.
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Cross-Country
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Alternator
Ok Franklin here we go. I think I will keep the 1 wire alternator so what I need to know how to hook up the wires that are in the harness. The I wire alternator is already hooked up.
The harness has a plug with 4 wires going into it. (1) yellow heavier wire. (1) red (1) green with black stripe (1) yellow with green stripe . Also there is (1) red wire separate of the harness with a push connector for one of the lugs on the solinoid ???. I'm almost sure that most of the 4 wires in the harness would connect to the battery or solenoid or not used at all. There are no connections on the one (1) wire alternator for any of these wires.
Now I'm sure you are totally confused .
Thanks again for your help my friend.
The harness has a plug with 4 wires going into it. (1) yellow heavier wire. (1) red (1) green with black stripe (1) yellow with green stripe . Also there is (1) red wire separate of the harness with a push connector for one of the lugs on the solinoid ???. I'm almost sure that most of the 4 wires in the harness would connect to the battery or solenoid or not used at all. There are no connections on the one (1) wire alternator for any of these wires.
Now I'm sure you are totally confused .
Thanks again for your help my friend.
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FTE Legend
Joined: Nov 2015
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From: Angier, NC
Can you take a picture or 3 of what you are working with ?
Picture of the solenoid and wires on it.
Harness wires and and connections it may have.
Also wire colors as I am having a hard time seeing in my head what you are saying
Dave ----
Picture of the solenoid and wires on it.
Harness wires and and connections it may have.
Also wire colors as I am having a hard time seeing in my head what you are saying
Dave ----
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Cross-Country
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Alternator
Hey DaveOk here we go. 1986 F250 460
I have a 1 wire alternator installed The alternator original harness which is located by the passenger side fender well near the solenoid has (4) wires. These wires all or some I believe need to be connected to the battery and or solenoid directly so I have ignition, lights etc.
(1. Yellow larger gauge wire(1. Green with black stripe(1. Yellow with green stripe(1 Red
there is also a red wire separate of the harness that has a plug for the solenoid lug..
The 1 wire alternator connects directly to the battery. No other wires connect to it.
I have a 1 wire alternator installed The alternator original harness which is located by the passenger side fender well near the solenoid has (4) wires. These wires all or some I believe need to be connected to the battery and or solenoid directly so I have ignition, lights etc.
(1. Yellow larger gauge wire(1. Green with black stripe(1. Yellow with green stripe(1 Red
there is also a red wire separate of the harness that has a plug for the solenoid lug..
The 1 wire alternator connects directly to the battery. No other wires connect to it.
FTE Legend
Joined: Nov 2015
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From: Angier, NC
Do you have a picture of the solenoid so we can see what is connected to it.
I will see if I can get a picture or 2 of my 81 F100 set up as I dont have any good pictures of either truck for us to go by on my web site.
Dave ----
I will see if I can get a picture or 2 of my 81 F100 set up as I dont have any good pictures of either truck for us to go by on my web site.
Dave ----
FTE Legend
Joined: Nov 2015
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From: Angier, NC
Well not good news 
I went out to take a picture or 2 and got looking at it and seen that it would not help much.
I say this because that round plug you have plugs into the ALT / REG harness and from what I can tell there are splices that double back to the solenoid for power.
My truck only has 1 wire (fuse link) on the solenoid power side.
As said it goes into the ALT harness and must double back to feed power to the truck inside.
Think it was black / red wire then taped in the harness. I dont see that color wire on the trucks harness side?
Hope DaveF can post up wiring for the solenoid & ALT to see what wire(s) need power.
It would be nice if you could get a ALT harness even if you dont use it just for the power tie in.
So lets go with what I do know. That Red / white with the 90* plug goes to the solenoid on the small post marked S.
When you do get power that wire should be hot when the key is turned to start.
I cant get to my old trucks harness till the weekend to see if it has a ALT harness.
From what I remember part of that harness was missing but the trucks power side I think was still there.
If so I might be able to open it up to see what wires go where.
DaveF where are you we need wiring pictures
Dave ----
I went out to take a picture or 2 and got looking at it and seen that it would not help much.
I say this because that round plug you have plugs into the ALT / REG harness and from what I can tell there are splices that double back to the solenoid for power.
My truck only has 1 wire (fuse link) on the solenoid power side.
As said it goes into the ALT harness and must double back to feed power to the truck inside.
Think it was black / red wire then taped in the harness. I dont see that color wire on the trucks harness side?
Hope DaveF can post up wiring for the solenoid & ALT to see what wire(s) need power.
It would be nice if you could get a ALT harness even if you dont use it just for the power tie in.
So lets go with what I do know. That Red / white with the 90* plug goes to the solenoid on the small post marked S.
When you do get power that wire should be hot when the key is turned to start.
I cant get to my old trucks harness till the weekend to see if it has a ALT harness.
From what I remember part of that harness was missing but the trucks power side I think was still there.
If so I might be able to open it up to see what wires go where.
DaveF where are you we need wiring pictures
Dave ----
FTE Legend
Joined: Nov 2015
Posts: 30,935
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From: Angier, NC
I dont know what one of them other wires on that plug needs power so you get power inside.
I got to see if I have that ALT harness I can open to see how the wires go.
Dave ----