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Believe it or not at some point, between trying to find a correct harness, or ending up making your own (which isn't that bad) the 3G conversion might actually be the easier choice.
I don't know that the '67 is the same (NumberDummy or one of the others will have to tell us) but I tend to doubt it. I bet the alternator end of the harness would fit the alternator, since many of them had the same orientation on the connections. But it's the other end where it ties into the rest of the harness that is probably different.
Just on the Broncos alone (which I'm more familiar with) there were probably four or five distinctly different alternator harnesses, even though every alternator was the same!
Can you post up a pic of the melted harness at both ends so we can see which one you have? If you still have it that is.
Basically though, if you're set against the 3G upgrade then in a pinch you can easily re-wire yours temporarily until you do the full re-wire.
But like I said earlier, the 3G swap is so easy (usually) that this might be just that impetus to do the new alternator because you have to mess with the wiring anyway. And when you do eventually re-wire the rest of the harness the existing 3G stuff should fit right into the new mix.
It will likely remain mostly, if not all the same.
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Believe it or not at some point, between trying to find a correct harness, or ending up making your own (which isn't that bad) the 3G conversion might actually be the easier choice.
I don't know that the '67 is the same (NumberDummy or one of the others will have to tell us) but I tend to doubt it. I bet the alternator end of the harness would fit the alternator, since many of them had the same orientation on the connections. But it's the other end where it ties into the rest of the harness that is probably different.
Just on the Broncos alone (which I'm more familiar with) there were probably four or five distinctly different alternator harnesses, even though every alternator was the same!
Can you post up a pic of the melted harness at both ends so we can see which one you have? If you still have it that is.
Basically though, if you're set against the 3G upgrade then in a pinch you can easily re-wire yours temporarily until you do the full re-wire.
But like I said earlier, the 3G swap is so easy (usually) that this might be just that impetus to do the new alternator because you have to mess with the wiring anyway. And when you do eventually re-wire the rest of the harness the existing 3G stuff should fit right into the new mix.
It will likely remain mostly, if not all the same.
Paul
here’s some before I start taking it apart to compare it to the ‘67 harness.
id like to buy a new 130A alternator with the soft start regulator once I put the rest of the engine back together. This alt is effectively new so I don’t mind getting it working as-is before I start the alt upgrade.
Easy-peasy. My alternator harness for my 72 burned up like yours in 1980. For about $20's worth of materials, I rebuilt it in my dorm room with hardly any electrical and mechanical knowledge. You can do it. For the 3G conversion, try this from Hotrod magazine: https://www.hotrod.com/articles/inst...r-older-fords/
Thanks for the pics.
Your existing wiring is not original anyway, so you can go any direction you want. And it may have been wired incorrectly, though if so it should have melted almost immediately upon the first start-up.
Looks like the wire that melted was a ground wire up at the fender, but if that's the same wire as connected to the stud with the black insulator that is most definitely NOT a grounding point!
When a ground wire melts, it's usually one of two things causing it.
1. The wire itself shorted to a power wire, but the power wire was of a larger gauge so the smaller ground wire took the hit.
2. The main engine ground failed and when you hit the starter all the current tried to find the next best thing. Giving that way-too-small ground wire something to write home about!
Other things that melt when the main cable fails are manual choke cables and metal throttle linkages.
Did this melt-down happen to take place during an attempt to start?
The connectors you're showing are keyed specifically, so if the '67 harness that you found does not share the same exact style then it won't be a simple plug-n-play like we'd hope. Very likely this is the case too, as that's exactly what Ford would change over the years whenever a harness was updated.
But in this case, are you sure you even need it? Looks like only one wire melted. But it does look like many of them are changed.
Do you have an ammeter in your instrument cluster, or does your truck have only indicator lamps for pressure and battery? Or is it temp and battery? I don't remember.
Another question related to the gauges is does your voltage regulator have three, or four wire positions used? Was it re-wired along with the alternator?
A pic of the regulator might be in order, along with the description of the dash. Someone in the past may have used the wrong wiring diagram to connect your charging system and it was just a melt-down waiting to happen.
Let us know if that wire that's totally fubar'ed is the only one, or if it perhaps touched the main BAT wire from the post on alternator with the red insulator.
Thanks for the pics.
Your existing wiring is not original anyway, so you can go any direction you want. And it may have been wired incorrectly, though if so it should have melted almost immediately upon the first start-up.
Looks like the wire that melted was a ground wire up at the fender, but if that's the same wire as connected to the stud with the black insulator that is most definitely NOT a grounding point!
When a ground wire melts, it's usually one of two things causing it.
1. The wire itself shorted to a power wire, but the power wire was of a larger gauge so the smaller ground wire took the hit.
2. The main engine ground failed and when you hit the starter all the current tried to find the next best thing. Giving that way-too-small ground wire something to write home about!
Other things that melt when the main cable fails are manual choke cables and metal throttle linkages.
Did this melt-down happen to take place during an attempt to start?
The connectors you're showing are keyed specifically, so if the '67 harness that you found does not share the same exact style then it won't be a simple plug-n-play like we'd hope. Very likely this is the case too, as that's exactly what Ford would change over the years whenever a harness was updated.
But in this case, are you sure you even need it? Looks like only one wire melted. But it does look like many of them are changed.
Do you have an ammeter in your instrument cluster, or does your truck have only indicator lamps for pressure and battery? Or is it temp and battery? I don't remember.
Another question related to the gauges is does your voltage regulator have three, or four wire positions used? Was it re-wired along with the alternator?
A pic of the regulator might be in order, along with the description of the dash. Someone in the past may have used the wrong wiring diagram to connect your charging system and it was just a melt-down waiting to happen.
Let us know if that wire that's totally fubar'ed is the only one, or if it perhaps touched the main BAT wire from the post on alternator with the red insulator.
Paul
it actually was still running/starting fine until I started the engine replacement and I didn’t notice the problem until I was taking the alt off the engine.
I’ll take some
I’ll need to look at the diagrams again but I think the only difference between 67 and 69 was the addition of a fuse.
I have an ammeter gauge which will be another item to deal with
where is the main engine ground strap usually at? I didn’t take one off during engine removal, but there is one between the alternator bolt to the battery.
i can get photos soon. I’m still not convinced that I should be trying to add/upgrade my power just yet, before I root out all the other electrical gremlins.
here’s some before I start taking it apart to compare it to the ‘67 harness.
id like to buy a new 130A alternator with the soft start regulator once I put the rest of the engine back together. This alt is effectively new so I don’t mind getting it working as-is before I start the alt upgrade.
First figure why someone wire the stator wire to chassis ground..... nothing like adding a direct short.
I’ll need to look at the diagrams again but I think the only difference between 67 and 69 was the addition of a fuse.
But just that change could easily have led to multiple changes in the design of the connectors.
Originally Posted by Brkdncr
I have an ammeter gauge which will be another item to deal with
I love ammeters, but the Ford design for the trucks was notoriously unreliable. And really had little accuracy even when it did work, due to there not really being usable graduations!
But with the ammeter, your alternator and regulator are wired with the marked terminals at the regulator connector like this:
1. I - Unused. The cavity on the connector should be empty.
2. A - Yellow. Always hot. Should have full battery voltage at all times whether the key is ON or OFF
3. S - Green w/red. Switched 12v with the key in the ON position only.
4. F - Orange. Field wire runs straight from the regulator to the FLD terminal of the alternator. This is the ONLY wire connected between the alternator and the regulator on your truck.
On the back of the alternator you will have:
1. BAT - Black wire from BAT terminal to the battery side of the starter relay/solenoid. Should be a minimum of 10ga but a little bigger would not hurt anyone's feelings.
2. FLD - Orange wire to the F terminal of the regulator. Here you can use 14ga wire.
3. GRD - Black wire from the alternator's case to one of the screws holding the voltage regulator to the core support.
4. STA - White w/black from the factory, but yours did not have one. Unless you are using an electric choke and need this connection, the STA terminal remains empty and serves no purpose on your truck.
For the ground wire to the regulator you can use any of the case bolts ore additional studs that attach to the body of the alternator. The one marked GRD is simply the most obvious. If it's convenient then, use it. If not, then one of the other grounding points will do.
Just make sure you do NOT have a wire to the main studs that does not go where it's supposed to. If any of them are routed incorrectly your alternator will not work.
Originally Posted by Brkdncr
where is the main engine ground strap usually at? I didn’t take one off during engine removal, but there is one between the alternator bolt to the battery.
That's it, but it's not in the most effective place. For the best, most reliable performance the main battery ground cable should be bolted directly to the engine block at a spot clean of oil, gunk, rust or paint.
Yes, millions of GM cars and trucks mounted theirs to the alternator bracket. But when everything is brand new it works passably well. After years of deterioration it's still not the best place to put it in my opinion.
Originally Posted by Brkdncr
I’m still not convinced that I should be trying to add/upgrade my power just yet, before I root out all the other electrical gremlins.
Not a bad choice. Just that any electrical problems with the charging system are by design fully rooted out when you change to the 3G because literally everything is fiddled with at the same time, and you would only need your Yellow and Green w/red wires remaining. And those can be repaired/replaced just as easily when going to a modern internally regulated alternator as they can when trying to make the old stuff work. Only easier...
But you're only getting a half-assed argument from me. I understand trying to get stuff dialed in with the existing stuff. Especially with a newer alternator that you want to get some use out of. That design worked for 20 years, so no reason it can't work on your truck.
It's more work to make the existing one function again, given the condition of your wiring, but it's pretty straightforward nevertheless.
What you really need to do is to verify that each of the wires I mentioned above goes where it is supposed to go and does what it is supposed to do.
When you do that, it should all work again unless the components have failed in the meantime. If you shorted the stator post to ground there's nothing that says your alternator is not damaged. But I've seen them survive worse too, so carry on and see what you find.
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Believe it or not at some point, between trying to find a correct harness, or ending up making your own (which isn't that bad) the 3G conversion might actually be the easier choice.
I don't know that the '67 is the same (NumberDummy or one of the others will have to tell us) but I tend to doubt it. I bet the alternator end of the harness would fit the alternator, since many of them had the same orientation on the connections.
TWO different harnesses, with or without oil and amp gauges is the difference.
1967 might be the same as 1968/69 if it has oil and amp warning lights and the '67 was assembled from serial number B26,001.
But there's a much simpler solution. The Mustang harnesses are reproduced, cars use the same alternators and regulators as the trucks.
Find a Mustang harness that is the same length or slightly longer, plug it into the alternator regulator, attach the other end to the alternator...problem solved.
Were some of the Mustangs of that vintage equipped with ammeters Bill? I believe I've seen Ford passenger cars with ammeters, but would not remember which ones, or if it was an incorrect memory.
If available then the harness the OP would want would be the one for the full gauges with ammeter so that the new harness connections correspond to the same existing ones on the truck.
Or if not available for gauges Brkdncr, but you still want to try one of the Mustang reproduction pieces, just make sure to re-pin your regulator so that the connections are changed to this:
1. I - Indicator/Ignition Green w/red wire now plugs in to this position.
2. A - Armature Yellow remains here.
3. S - Stator White w/black stripe from here to the STA terminal of the alternator.
4. F - Field wire is unchanged and still goes to the same place on the alternator.
The new harness is likely already set up between the regulator and alternator, so it's just up to you to make sure that the connections from your main harness match the wire colors of your new harness. The function of each colored wire remains the same, but the way they get the job done and their locations on the regulator differs between ammeter equipped vehicles and those with indicator lights instead.
Were some of the Mustangs of that vintage equipped with ammeters Bill? I believe I've seen Ford passenger cars with ammeters, but would not remember which ones, or if it was an incorrect memory.
One thing you can do to help stop electrical problems is add larger and more grounds. The auto industry has always used the smallest (thinnest) ga wire that they could get away with. Just a small amount of corresion, rust, or loos bolt and you start to have problems.
Many of us have added wires from the battery to the frame. Then from the frame to the engine. Add one from the engine (normally from the intake manifold to the cab. And run a wire from the mounting studs of the heater over to the passenger side inner fender. I also extended the ground wires for the headlight and the turn signal lights and ran them up to the mounting bolt for the voltage regulator. I try to always use stainless steel washers, along with nuts and bolts- just because I'm getting too old to go back and replace last years rusty bolts. And I ALWAYS use AT LEAST the next size larger wire, than what was original.
My battery has dual posts so I was able to run 2 wires from the battery posts Ground wire extension from the headlights and turn signal lights. The yellow wire goes to the horn, which was removed in the pic.
Here's one company that makes the harnesses for Mustangs. They do not list them for either pickups or Broncos, but do show a relatively inexpensive version for a '67 Mustang with full gauges. https://www.ynzyesterdaysparts.com/h...ing-harnesses/
I confirmed that i have the full instrument cluster. I have an ammeter gauge, oil gauge, etc. This is a 1967 camper special so that makes sense if it was designed to hold a 2nd battery.
My harness is in worse shape then originally thought. There were multiple nicks, splices, and wiring that changes color once or twice. The wiring that failed melted some other wires on its way out.
the 1967 harness is not a drop-in replacement, but it's close. I know the STA connection on the alt was supposedly not used, but the previous harness had it connected, so i'm connecting it on mine.
So what I'm going to do is remove the 2-way connector for wire 904 (904 is labeled "Coil Terminal of ignition switch alternator regulator and is green/red tracer) and splice it into my leftover connector for the 4-way connector, which is labeled as the same 904. The 3-way connector also has ammeter wiring 37 and 654. These are shown as spliced all together in the same black 8ga cable that goes between the BAT on the alternator and the power source side of the starter relay. For simplicity i'm just going to put ring terminals on these and bolt them down to the starter relay BAT post.. If you're still following along there's an open connectory on that 4-way connector. There is also an open connector on the 2-way, and it looks to unrelated to the charging system on both (it's for the horn).
The hardest part so far was figuring out how to get the alternator wiring to line up. The rubber covers matched the alternator just fine, but the ground seemed too short and the BAT seems too long. There was also a ground wire (black, red tracer) with a large ring terminal that didn't have a place to go. i thought it was supposed to connect between the engine and the alt on the bottom alt bolt but that didn't fit right. I ended up using a bolt hole on the engine block. It feels like there's a lot of strain on the crimp connectors. i'm not a fan of there being any strain at all on connectors, but it seems like this is what Ford was doing in '69.
Looking at the wiring connectors for '69 mustangs didn't show anything that had the same 4-way connector that mine does. If i didn't already have the '67 harness i'd probably call up ynzyesterdaysparts.com as recommended to see what they have.
I'm happy with how this ended up, and if when I eventually start it up and all the smoke escapes then I'll simply order the painless full harness replacement kit. There's a lot of splices and new wires from electrical adventures of previous owners that I'd rather just fully replace then keep stumbling over.
If everything works out, I'll tackle a 3g upgrade later when I decide how to deal with the ammeter. i'm not a fan of having a non-functional gauge so I might need to get it rebuilt or replaced to read voltage.
If everything works out, I'll tackle a 3g upgrade later when I decide how to deal with the ammeter. i'm not a fan of having a non-functional gauge so I might need to get it rebuilt or replaced to read voltage.
11-17-2020, 11:19 AM
