A question for all you electrical Gurus

[Rich Ackermann 174]

Hi Randy and other Ford wiring Experts,

I installed a Tuff Stuff 140 amp Ford 1G Hybrid Alternator and a Tuff Stuff electronic Regulator in my 70 Mach 1 with a factory tachometer. I modified the stock wire harness according to the Tuff Stuff instructions  (see below). I am using the factory wire harness from the regulator.

Regulator Terminals

(I = Ignition (#904 Green/Red Stripe) to Alternator Warning Lamp and Ignition Switch (where #904 also connects to #297 Black/Green Stripe) as shown in the Ford Charging/Prove-out wiring diagram.

A = Battery (#152 Yellow) to Tuff Stuff Alternator Red wire

S = Stator (#4 White/Black Stripe) to Tuff Stuff Alternator Yellow wire

F = Field (#35 Orange) to Tuff Stuff Alternator Green wire

The Alternator is running and charging great...no operational issue there. My issue is the Alternator light stays on and will not turn off. I called Tuff Stuff Tech and they told me I did not need to connect the I (ignition) wire (#904 Green/Red Stripe) from the regulator. 

I disconnected the I (ignition) wire (#904 Green/Red Stripe) and started the car everything appears to be working normally with this wire disconnected and the Alternator Warning Lamp is off. 

I am uncomfortable with having the  I (ignition) wire (#904 Green/Red Stripe) from the regulator. disconnected as Ford put it there for a reason. Since other wires (#297 connects to the Ignition Switch and #640 connects to the other terminal on the Alternator warning lamp)) in the Ford harness are connected. Finally the Warning Lamp is now disabled. Fortunately I have a Volt Meter gauge as well, so I can live without the warning light.

Does anyone who understand how the Warning Lamp work as Ford intended it to see a problem with disconnecting (I = Ignition (#904 Green/Red Stripe) from the Regulator?

For my own edification, how does the Regulator and Alternator Warning Lamp circuit actually work to cause the Lamp to light?

Thanks,

Rich

[Mach1 Driver 560]

Rick, if you want to understand how the OE system works, go to "How tos" on this forum, and read my paper "How Alternators Work". It will explain both types of systems used on our cars- those with and without the alternator light. Your new regulator doesn't work like the old one and the warning light is just disconnected in your case. Your voltmeter will tell you what is happening, and is much better than the ammeter used on my car. Unfortunately manufacturers try to make this stuff so generic, that their instructions are next to useless.

What did you do in step 7? The reason I ask is because you replaced about a 38A alternator for a 140A, and one of the things they don't seem to tell you is that it could smoke Black wires 38 and 38A, if its cranked up all the way during charging. The wire gauge size is just inadequate, however they are short wires so that may save them- but I'll bet they get hot. Most people that install these humongous alternators attach a heavy gauge battery cable to the alternator positive, that goes to a mega fuse (around 200A) and that attaches to another cable and then to the left solenoid terminal.

Hopefully Midlife can chime in here, because I don't have a 70 wire diagram and I know that the 70s were the first year to have a fusible links...I'm guessing from the solenoid left terminal to wire 37 and possibly some other wires?? It isn't shown on your diagram so we need that bit of the puzzle before making a thorough recommendation.

[Rich Ackermann 174]

3 hours ago, Mach1 Driver said:

Rick, if you want to understand how the OE system works, go to "How tos" on this forum, and read my paper "How Alternators Work". It will explain both types of systems used on our cars- those with and without the alternator light. Your new regulator doesn't work like the old one and the warning light is just disconnected in your case. Your voltmeter will tell you what is happening, and is much better than the ammeter used on my car. Unfortunately manufacturers try to make this stuff so generic, that their instructions are next to useless.

What did you do in step 7? The reason I ask is because you replaced about a 38A alternator for a 140A, and one of the things they don't seem to tell you is that it could smoke Black wires 38 and 38A, if its cranked up all the way during charging. The wire gauge size is just inadequate, but they are short wires so that may save them- but I'll bet they get hot. Most people that install these humongous alternators attach a battery cable to the alternator positive, that goes to a mega fuse (around 200A) and that attaches to the left solenoid terminal.

Hopefully Midlife can chime in here, because I don't have a 70 wire diagram and I know that the 70s were the first year to have a fusible links...I'm guessing from the solenoid left terminal to wire 37 and possibly some other wires?? It isn't shown on your diagram so we need that bit of the puzzle before making a thorough recommendation.

Your point about the inadequate wire size is an excellent one, and was something I realized from the beginning, so with the new Alternator I ran a 6 AWG wire (which is what Tuff Stuff recommended) to a Terminal Block I installed. I have a 4 AWG wire from the terminal Block to the battery post. The factory black wire and the 904 Green/Red Stripe in the factory harness two pin plug now go to the battery post as well. The rest of the factory harness to the regulator is the same as it was. I also have a 10 AWG wire from the Alternator case to Chassis/Block ground. I question Tuff Stuff as to why the ground does not need to be 6 AWG like the positive wire, and they said the Alternator case is also grounded thru the mounting brackets to the block. Finally my Starter and Sub amp come directly off the battery terminal and are both 4 AWG. The Stater has a secondary 8 AWG wire from the Solenoid and the Sednoid has a 6 AWG wire to the battery post.

Step #7 I ran 6 AWG wire from the Alternator to a Terminal Block and a 4 AWG wire from the terminal block to the battery post.

All that said, I think I have made sure that all my electrical wire size is sufficient. I just spent the past hour drawing up an electrical diagram. I am no artist but I think I have clearly depicted what I have with the wire sizes.

[Mach1 Driver 560]

Did Tuff Stuff say its ok to connect to regulator A and I? Nothing is shown on the instructions that I can see. Most people would put a mega fuse on the 6ga from the alternator to terminal block. Wire 37 is power to most of the car, so if there is a fuse link I would expect it between 37 and 38, or upstream from 38 to the terminal block.

[Mach1 Driver 560]

51 minutes ago, Rich Ackermann said:

The factory black wire and the 904 Green/Red Stripe in the factory harness two pin plug now go to the battery post as well.

The black wire you are referring to is 38?

Power goes from battery+, to the terminal block, to 38, to 37, to the ignition switch B, to C in ON and Start, then back via 904 red/green to the battery+ again? That sounds like it is going nowhere. To alleviate any problems I would just remove 904, since it doesn't do anything anymore. As I mentioned earlier, I don't believe your wire diagram is 100% correct. I have found a number of problems on many wire diagrams- even my own Ford authorized drawing is incorrect in several places.

[Rich Ackermann 174]

1 minute ago, Mach1 Driver said:

Did Tuff Stuff say its ok to connect to regulator A and I? Nothing is shown on the instructions that I can see. Most people would put a mega fuse on the 6ga from the alternator to terminal block. Wire 37 is power to most of the car, so if there is a fuse link I would expect it between 37 and 38, or upstream from 38 to the terminal block.

When I talked to the tech at Tuff Stuff, I told them that I was using the stock harness and regulator plug. My focus was on terminal "I" and the warning light on. The Tech told me to disconnect "I", which bring us full circle and my reason for this post. I am uncomfortable with having the  I (ignition) wire (#904 Green/Red Stripe) from the regulator. disconnected. Ford put it there for a reason.  I would prefer to have the Warning Light working as it was intended, but I would prefer to get confirmation that there is no harm with disconnecting it.

I did ask the Tech about fusing the wire to the Alternator. He said and I quote "Don't waste your money fusing it"

[Mach1 Driver 560]

Rich, you have already stated "The Alternator is running and charging great...no operational issue there. My issue is the Alternator light stays on and will not turn off. I called Tuff Stuff Tech and they told me I did not need to connect the I (ignition) wire (#904 Green/Red Stripe) from the regulator". 

They have told you to disconnect wire 904. Their regulator is electronic and doesn't function the way the electro-mechanical one does. I would ask them if anything needs to be connected to A, but according their document it doesn't.

If you want to know how the OEM system operates, then take the time to read my paper- it is too lengthy to be discussed here. Besides, you're not using it anymore. The Tuff Stuff system is "electronic", while the OEM system is many decades older and "electro-mechanical". A tech on the phone is unlikely to have knowledge of the internal workings of their circuit. Its an apples and oranges comparison. They don't need the same inputs and outputs, and they won't publish details of the internal workings. Welcome to the wonderful world of generic aftermarket parts.

[Rich Ackermann 174]

5 minutes ago, Mach1 Driver said:

The black wire you are referring to is 38?

Power goes from battery+, to the terminal block, to 38, to 37, to the ignition switch B, to C in ON and Start, then back via 904 red/green to the battery+ again? That sounds like it is going nowhere. To alleviate any problems I would just remove 904, since it doesn't do anything anymore. As I mentioned earlier, I don't believe your wire diagram is 100% correct. I have found a number of problems on many wire diagrams- even my own Ford authorized drawing is incorrect in several places.

Yes. The black wire #38 10 AWG which originally connected to the stock Alternator and thru a 2 pin  plug to the Battery side of the regulator and also to the #37 Black/Yellow Accessory wire, now goes directly from the terminal block to the #37 Black/Yellow Accessory wire. The new 6 AWG wire goes from the T. S. Alternator directly to the terminal block.

The path according to Ford #904 red/green wire goes from the I term on the regulator to the other pin in the 2 pin plug along with Black wire #38 then to the gauge cluster plug where it splits and one wire goes to the Alt warning lamp and the other goes to the large pin on the ignition switch plug, where it is joined with The Black/Green #297 wire. I have changed nothing with wire #904, and other than removing #38 wire from the battery side of the Solenoid and relocating the 10 AWG #38 wire from the original Ford alternator to the terminal block, where it now meets up with the new 6 AWG wire from the T. S. alternator.

[Mach1 Driver 560]

28 minutes ago, Rich Ackermann said:

I did ask the Tech about fusing the wire to the Alternator. He said and I quote "Don't waste your money fusing it"

The techs are not familiar with individual year cars. Most of the car is unprotected- count the number of fuses in the block. Mine has only five fuses. Nothing in the ignition system is fused. The lights have two circuit breakers, but only after the wires get to the light switch. The gauges have nothing, the charging has nothing. The list goes on. Large portions of your main harness is unprotected. IMO a fuse on the alternator is warranted, but suit yourself. Ford did add fuse links somewhere on the 70s, but it's not shown on your diagram.

[Rich Ackermann 174]

12 minutes ago, Mach1 Driver said:

Rich, you have already stated "The Alternator is running and charging great...no operational issue there. My issue is the Alternator light stays on and will not turn off. I called Tuff Stuff Tech and they told me I did not need to connect the I (ignition) wire (#904 Green/Red Stripe) from the regulator". 

They have told you to disconnect wire 904. Their regulator is electronic and doesn't function the way the electro-mechanical one does. I would ask them if anything needs to be connected to A, but according their document it doesn't.

If you want to know how the OEM system operates, then take the time to read my paper- it is too lengthy to be discussed here. Besides, you're not using it anymore. The Tuff Stuff system is "electronic", while the OEM system is many decades older and "electro-mechanical". A tech on the phone is unlikely to have knowledge of the internal workings of their circuit. Its an apples and oranges comparison. They don't need the same inputs and outputs, and they won't publish details of the internal workings. Welcome to the wonderful world of generic aftermarket parts.

I look forward reading your paper thoroughly. I will call them and get clarity on term A wire as well.

Anyway, I thank you very much for taking the time to answer my questions in an effort to sort this out.

Regards,

Rich

[Midlife 814]

Fusible links were put in place to protect the battery and nothing else.  In 1970, they were introduced, but if the car was running, there was still a hard wire from the alternator output to the entire car.  The fusible link was the last 9 inches of wire from the alternator to the battery.  If the link blew (let's say due to an overcharging alternator), the car will still run and the remaining wires would or would not handle the current load.  When the car stopped running, the battery would now be out of the circuit (due to blown fusible link) and you wouldn't be able to provide power to the ignition switch to start the starter. 

In 1971, Mustangs still had fusible links, but those cars that had ammeter still had a hard-wire path from the alternator directly to all wiring on the car.  Those with indicator lamps that happen to blow the fusible link would immediately die.

Fusible links were not well implemented, IMHO.

As for your charging problems, Mach1Driver knows more than I regarding this.  Once you get away from a stock system, I'm as clueless as Seattle.  I agree that with a voltmeter, you can disable the indicator lamp.

[Mach1 Driver 560]

11 hours ago, Midlife said:

The fusible link was the last 9 inches of wire from the alternator to the battery.

Mid, so from your description I'm guessing that wire 38A is the fusible link? Its probably just a wire that is a gauge or two smaller than wire 38.

[Midlife 814]

Yes on both accounts.  I'm not sure whether the 38A wiring is just standard copper stands or something different.

[Mach1 Driver 560]

28 minutes ago, Midlife said:

Yes on both accounts.  I'm not sure whether the 38A wiring is just standard copper stands or something different.

I have read that its just regular copper wire- but smaller, so it should blow first in a high amp condition. By chance do you know the gauge sizes for 38 and 38A on the 1970?

[Rich Ackermann 174]

6 hours ago, Mach1 Driver said:

I have read that its just regular copper wire- but smaller, so it should blow first in a high amp condition. By chance do you know the gauge sizes for 38 and 38A on the 1970?

 

Here is a picture of a portion of the alternator wire harness I removed when converting to the 140amp Tuff Stuff Alternator. The 1970 wiring diagram says Black wire 38 and black/yellow accessory 37 wire are 10 Gauge. Yellow 21 Ignition switch Accessory is 12 gauge. Although missing from my harness the 38A  fusible link pigtail to the battery side of the solenoid branched at the connection of wires 38 and 37.

I cannot confirm what year the wire below is from, but here is a picture of the end of 38 and Fusible Link 38A. You can see the fusible link on wire 38A which is the lead to the battery side of the solenoid. It says 14 G.A and Black wire 38 is 10 gauge to the 2 pin plug is missing on the end. This wire is setup differently with the yellow wire 152 junction in the middle rather than at the plug as it is on my 1970 wire.

 

 

 

[Mach1 Driver 560]

Tuff Stuff says that the alternator has a Ford style front case, a GM style rear case with heavy duty copper coils, spike resistant diodes, and an external solid state voltage regulator. From experience you know that the regulator can't be connected as the OEM regulator was. This is a combination of parts that doesn't operate the way the old system did, and you will never know what goes on inside their regulator.

So, here are my recommendations:

1. Remove or disconnect and tape wires 904, 152, and 38. You will not have an alternator warning light.

2. Connect a 14ga fuse link between wire 37 and the terminal block. Do not bundle the fuse link into a harness with other wires- let it hang loose so if it melts it doesn't destroy other wires or harnesses. Its a fuse so let it do its job. If you need a source for this I can find it.

3. Put a mega fuse between the alternator battery terminal and the terminal block.  

[Midlife 814]

That fusible link is not a factory correct 1970, as in my experience (close to 125 1970 refurbishments), I have never seen the green flag on any of the power leads: just a black wire, perhaps with some writing on it.  The flags first appear in 1971. 

There is another useful thing about fusible links that I failed to mention above: if the car is sitting in a garage, not on, and somehow a massive short is initiated, the fusible link will prevent current flowing from the battery and thus the rest of the wiring is protected to a certain degree.  It will definitely stop an electrically induced fire when the car is off or the key is in ACC or RUN but with the engine not running.  Perhaps that was the reason it was implemented. 

As far as wire gauges go, what Ford used and documented is somewhat inconsistent with what is typically found today in wire sizes.  I suspect there was either a change in AWG specifications or Ford used a slightly different gauging system that what is currently used today.  When I buy 18 gauge wiring, it is somewhat thicker than the Ford product when the insulation is removed.  The fusible link does appear to be about 2-4 AWG sizes less than the main power line.

[Rich Ackermann 174]

13 hours ago, Mach1 Driver said:

Tuff Stuff says that the alternator has a Ford style front case, a GM style rear case with heavy duty copper coils, spike resistant diodes, and an external solid state voltage regulator. From experience you know that the regulator can't be connected as the OEM regulator was. This is a combination of parts that doesn't operate the way the old system did, and you will never know what goes on inside their regulator.

So, here are my recommendations:

1. Remove or disconnect and tape wires 904, 152, and 38. You will not have an alternator warning light.

2. Connect a 14ga fuse link between wire 37 and the terminal block. Do not bundle the fuse link into a harness with other wires- let it hang loose so if it melts it doesn't destroy other wires or harnesses. Its a fuse so let it do its job. If you need a source for this I can find it.

3. Put a mega fuse between the alternator battery terminal and the terminal block.  

That's correct the alternator is considered and hybrid front Ford and rear GM to accommodate the larger internals needed for the 140amp. I understand and will do 1, 2, and 3. Thanks so much!

Question for you and Randy, Any reason not to use a manual reset breaker instead of a Fusible link?

[Rich Ackermann 174]

11 hours ago, Midlife said:

That fusible link is not a factory correct 1970, as in my experience (close to 125 1970 refurbishments), I have never seen the green flag on any of the power leads: just a black wire, perhaps with some writing on it.  The flags first appear in 1971. 

There is another useful thing about fusible links that I failed to mention above: if the car is sitting in a garage, not on, and somehow a massive short is initiated, the fusible link will prevent current flowing from the battery and thus the rest of the wiring is protected to a certain degree.  It will definitely stop an electrically induced fire when the car is off or the key is in ACC or RUN but with the engine not running.  Perhaps that was the reason it was implemented. 

As far as wire gauges go, what Ford used and documented is somewhat inconsistent with what is typically found today in wire sizes.  I suspect there was either a change in AWG specifications or Ford used a slightly different gauging system that what is currently used today.  When I buy 18 gauge wiring, it is somewhat thicker than the Ford product when the insulation is removed.  The fusible link does appear to be about 2-4 AWG sizes less than the main power line.

Randy,

Yes, I am not sure what year Mustang the Fusible link wire is from. I know its not from my 70 Mustang. 

Any reason not to use a manual reset breaker instead of a Fusible link? Does your point about protection from a massive short while the car is parked work with a Breaker as well? I would think so. How many sizes smaller is best? or example use a 14AWG fusible link wire with a 10 AWG wire or 12AWG fusible link wire with a 10 AWG?

Thanks as always for your help.

Rich

 

[Midlife 814]

Circuit breaker is not a substitute for a fusible link, as with a massive short, it will simply switch on and off repeatedly.  I believe (please don't quote me) that the fusible link needs to be 4 AWG sizes larger than the main power line.

[Mach1 Driver 560]

As you probably know, when the gauge number gets bigger, the wire size gets smaller. The fuse link needs to be smaller than the wire its protecting. In the past I have seen fuse links 2 wire sizes smaller than the wire they are protecting. I just googled it and found two references that say it should be 4 times. That would say a 10ga wire should have an 18ga fuse link (10, 12, 14, 16, 18...). While that is certainly safe for the protected circuit, I tend to think you may get nuisance tripping at 4 times, and personally would go with 2. I base this on Ford's use of a 14ga fuse link on a 10ga wire.

EDIT: I did further investigation and found that you have to count ALL wire gauges. Normally we only use the even number gauges, but a fuse link site said to count all even and odd sizes, and the fuse link should be 4 sizes smaller, so my example about Ford above is correct. American Wire Gauge Sizes are 8,9,10,11,12,13,14,15,16,17,18, etc. If protecting a 10ga wire the correct fuse link is 14ga. which is four sizes smaller. Mystery solved.

[Rich Ackermann 174]

4 hours ago, Midlife said:

 

 

4 hours ago, Midlife said:

Circuit breaker is not a substitute for a fusible link, as with a massive short, it will simply switch on and off repeatedly.  I believe (please don't quote me) that the fusible link needs to be 4 AWG sizes larger than the main power line.

Randy,
I was thinking of a Manual Reset Low Profile ATC Circuit Breaker.  Essentially an ATC type fuse that can be reset. An auto reset breaker would be pointless.

Thanks

[Mach1 Driver 560]

I was looking to see if I could find a time vrs current chart for fuse links to compare it to a circuit breaker time/current chart. I haven't been successful yet, but I did find clarification on the selection criteria for fuse links. See my EDIT two posts above. Now it finally makes sense to me.