Please help! 1969 F100 charging issues.

Charging, starting, lighting, gauges, HVAC

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DenverWolfman
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Please help! 1969 F100 charging issues.

Post by DenverWolfman »

Hello all, my name is Steve and I an a brand new member of this board as of this weekend. I bought my 1969 F100 2wd last year and up until then I have absolutely no experience in working on old cars. I got the truck for seemingly a good deal and it started and ran and I just went with it. Now, almost a year later, with the help of reading this forum and studying the schematics that are posted in the tech section, I am very comfortable getting down and dirty and working on this beast. His name is "Hank" by the way. According to the VIN this truck was born with a 6 cyl and it was swapped with a 289 V8 long long ago. According to the stamps on the block and intake manifold this motor came from a 69 Galaxy 500. I'm starting to think that this truck was Mickey Moused and Frankenstein'd throughout the years because I can't seem to find the exact wiring schematics for this thing.


Anyways, I am focusing on my charging system right now and the problem is that it's not charging at all. I replaced the alternator a few months ago after the original froze up on me. I also replaced the battery with a new one because the one it came with was almost 11 years old. I had a different parts store bench test the alternator and battery last week and they function as they should. I replaced the Voltage regulator with a new one that also tests fine.

Here is my problem, and likely confusion. According to the 1969 Ford Truck Shop Manual, trucks with alternators up to a 60 AMP size use the Electro Mechanical Alternator regulator (with 4 terminals) and those with 65 AMP or larger use the transistorized alternator regulator (with 3 terminals). In addition, there seem to be 2 different set ups with a charging indicator light and an ammeter. My truck has a 60 AMP alternator and I also have an ammeter on my dash instead of the charging indicator.

The wiring diagram in the 1969 truck section of fordification says its for a 65 amp 81 and 85 model and it shows the transisterized alternator regulator with an outboard field relay. with a truck like mine that has only a 60 amp alternator, a 4 post electro machanical regulator, as well as an ammetor im not exactly sure what wiring diagram to follow. The closest one that I can tell is the one labeled F100 to F350 guages models 81 and 85. apparently the S terminal on the regulator isnt used. Anyways, long story short Im at my witt's end with this. All the pieces are new and I've even gone as far as completely rebuilding the alternator wiring harness with all new correct gauge wire and connectors. I have the ammeter wire fused on both ends with 5 amp fuses as shown.

with a fully charged battery my truck starts and runs fine without any additional load like the headlights or wipers and the portable voltmeter reads about 12.50 volts. with the lights on it reads about 12.25 volts or so and I can watch it count down 1/100 th of a volt at a time every second or so. This translates to if I drive it at night for about 45 or 50 minutes straight my battery is drained down to the point where my truck just dies on the road. Anyways, bottom line is my system isnt charging and I've gone through it inch by inch and I cant find the problem. I did discover that if I jump the wire attached to the F terminal with the wire attached to the A terminal the the voltmeter jumps up to about 14 volts at idle and if I slightly increase RPM it will read up above 15 volts. This shows me the system is capable and the components work but there is something not jiving.

Today I got under the dash and looked at the ignition switch and wiring harness and 2 of the wires just pulled out with the slightest touch so I ordered new ones that will arrive in a few days.

It seems to me that there are other wiring schematics available that just aren't linked to on this website. I need ignition, charging, and guages for F100 with a 60 amp alternator and an ammeter.

by the way, how do i know if i have a model 51 or 55?
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sargentrs
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Re: Please help! 1969 F100 charging issues.

Post by sargentrs »

:wel: from Georgia! Nice truck. Hopefully one of our electrical gurus who has more technical knowledge will chime in. For me, having had several mismatched components on vehicles before, I don't think it really matters whether you have a 60 Amp, 65 Amp, volt gauge or amp gauge. The variations are in the connections to the gauge cluster, not the alternator charging the battery. The '69 F100-F350 model 81/85 diagram will suffice for troubleshooting. First off, make sure your ground on the Voltage Regulator is well connected. Clean the mating surfaces on the radiator support and the VR. Install with fresh screws or use bolts, nuts and star washers to mount it. Then check all of the other wires leading from your VR to their various connection points and make sure the terminals have good crimps, terminal ends, and are securely connected to where they should. The biggest culprit I've had was on wires #152 and #38 where they connect at the starter solenoid. I've had a couple of different occasions where the crimp was not secure on the ring terminal and the wire just pulled out with a slight tug.
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
DenverWolfman
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Re: Please help! 1969 F100 charging issues.

Post by DenverWolfman »

Hey there Randy thank you for the response. I will check those simple things this morning. I spent all day yesterday repairing my main wiring harness inside the dash. I ended up pulling it out yesterday morning and bringing it inside out of the cold. I discovered that a couple of the wires underneath the tape had been melted a little and the insulation was missing. I also discovered that the ignition switch was not wired correctly and completely. On the day that I bought the track the previous owner had just gotten back from the auto parts store because he said that him and his friends had “fried” the harness. I remember when I was there waiting his friend was connecting the wires underneath the dash and he had tried unsuccessfully several times with different combinations. Anyways, to make a long story short, I finally pulled the wiring harness out and with the help of all of the schematics Sean on this page I was able to repair a couple things and rewire my ignition switch. I’m going out now to spend the morning installing everything and I’ll report back.
DenverWolfman
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Re: Please help! 1969 F100 charging issues.

Post by DenverWolfman »

I do have a question about wiring my ignition switch though. In the diagram for all of the lights and turn signals It shows the black green stripe wire number 297 wired into the A position but In the diagram for gauges it shows that it’s wired into the C position And then the resistor wire and red green stripe wire is connected to the A position. Does it matter and if the resistor wire is not properly connected could that contributed to some of my electrical problems?
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sargentrs
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Re: Please help! 1969 F100 charging issues.

Post by sargentrs »

Ultimately, the resistor wire leads to the + side of your coil. On earlier models it's typically green/red. On '70+ I think it's black or maybe black/yellow. On my phone and hard to see the diagrams but I believe you should have a 3 prong plug leading from your firewall containing the temp sender, oil pressure sender and ignition wire to the coil. It's the "D" plug in this diagram http://www.fordification.com/tech/wirin ... arging.jpg. That ignition wire traces back to the resistor wire. Usually ends at the ignition switch together with the Run wire, the C terminal on the '69 switch. I can't read the terminal numbers on the '70+ diagrams :x
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
DenverWolfman
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Re: Please help! 1969 F100 charging issues.

Post by DenverWolfman »

OK, so two days ago I ended up pulling out the entire main wiring harness in the dash. Late this afternoon I finished reinstalling it after I pulled all of the old electrical tape off and inspected it inch by inch. I discovered that the main power line to my battery was fried all the way through the insulation and two wires next to It were stuck to it. Also the red four prong connector at the firewall was melted along that same wire. I Also discovered that three of my fuses were tripped as well as two wires were not installed on the ignition switch correctly and the number 16 resistor wire was missing entirely. Needless to say after I carefully Rebuilt The problem areas and reinstalled everything my truck runs like a beast. At idle it registers at 14.3 V right on the nose And with the ignition turned off my battery read at 13.2 volts. After a long and miserable, confusing, and sometimes absolutely stressful year of troubleshooting this thing I finally got it right.
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sargentrs
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Re: Please help! 1969 F100 charging issues.

Post by sargentrs »

Congratulations! That was an impressive undertaking and an indicator that she's found a home with the right owner. :clap: Not many people would have gone to that much effort and detail to chase down a wiring issue. :thup: to you and thanks for posting your fix!
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
DenverWolfman
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Re: Please help! 1969 F100 charging issues.

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Thank you sargentrs, I needed to finally solve this as this is my work truck and my Only transportation. I can’t tell you how many times I’ve been stranded in the morning or on the side of the road because my battery died Over the past year. Just when I think I had found the problem and started with a fresh battery charge I would go a few days and then the same thing would happen. Being in the summertime, it was especially difficult because I wouldn’t drive with my headlights on that often and my car would last a week or more sometimes. I finally said to myself that this is a 50-year-old car with no computers or sensors or anything complicated like that And it can’t be that hard to figure out. With a little perseverance I was able to finally do it. I’ve taught myself a lot of things on this truck and most of the time it’s just about using some common sense and simple troubleshooting trial and error. What a huge weight lifted off my shoulders now that winter is here. My next project? I have a set of 289 heads that I had rebuilt two months ago but just haven’t had the time to install them yet. This truck is my sanctuary and I can spend all day tinkering with it and forget about my problems.
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sargentrs
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Re: Please help! 1969 F100 charging issues.

Post by sargentrs »

DenverWolfman wrote:This truck is my sanctuary and I can spend all day tinkering with it and forget about my problems.
I think we all feel that way. I like to call it Bump Therapy. Cheaper than counseling. :lol:
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
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