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Discussion Starter · #1 ·
I downloaded the instructions someone posted on how to switch a '65 non-GT car over to the '66 round style instrument cluster, but I am still a little confused. Behind the ammeter on the cluster is a metal loop with a hole. Below that are two phillips head screws. I can't figure out how to hook this thing up. The cluster was insalled before, but I can't say with certainty that the ammeter was actually working.

Are there two wires running to the ammeter or one? Does something go through the loop to read amps?
 

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It's been years, but when I did my conversion I recall running two wires, a yellow and a red one according to an article in a Mustang magazine to the ammeter. As you probably know you done run full current through the meter because it is a shunt system. Don't know what the loop is for. Can you shoot a photo and post it here? Besides new ammeter wiring, about the only electrical change was cutting the signal light wire and adding another socket so you'd go from one signal light to two. To brighten the meters, I also painted over the chrome inside and added a light socket just to the left of the gas gauge and to the right of the temp gauge. The white paint alone will leave you with some non uniform lighting. I also got rid of the blue bulb covers, using a sharpie to tint the bulbs.
 

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VictorII describes the 1966 version of the ammeter, which uses two leads. The 1965 version uses an inductive loop, but I've never seen in person how to connect it to the wiring harness. I presume the wire goes through the inductive loop on the back of the ammeter, but that is pure speculation. The actual gauges are different between the two years.
 

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Discussion Starter · #4 ·
Here is a picture of the loop. Maybe someone can describe how to hook it up.

http://forums.vintage-mustang.com/files/attachments/med_1178233846-IMG_1106.JPG
 

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Midlife said:
VictorII describes the 1966 version of the ammeter, which uses two leads. The 1965 version uses an inductive loop, but I've never seen in person how to connect it to the wiring harness. I presume the wire goes through the inductive loop on the back of the ammeter, but that is pure speculation. The actual gauges are different between the two years.

What Mid said. The wire goes through the metal loop. That said, you won't notice any difference if it is wired correctly or not! The gauge never moves...

Also - if it was converted from the Falcon style cluster it is entirely possible that they never bothered with the conversion from the idiot light as it is pretty involved.

This is just one of the many reasons I went with new gauges!
 

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Discussion Starter · #6 ·
Let me make sure I understand this correctly. The two leads from the engine compartment are the same as for the later style. One lead is run through the loop and connected to the other lead creating a closed circuit. Is that correct?
 

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Joe6pack said:
Let me make sure I understand this correctly. The two leads from the engine compartment are the same as for the later style. One lead is run through the loop and connected to the other lead creating a closed circuit. Is that correct?
No, I don't think so. I suspect in 1965, there was a single wire that ran through the loop and connected to the other wire elsewhere. Exactly where, I haven't a clue. The circuit starts at the solenoid battery post, goes through the firewall, through the loop, back out through the firewall and connects to the alternator-battery harness, basically at the alternator junction. In 1966, that loop was separated into two separate hot leads, each lead plugging into the two posts on the ammeter.

BTW, thanks for the pic of the backside of the 1965 ammeter! First one I've seen!
 

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Never seen one like that. It looks like a light socket holder but I'm pretty sure it isn't since it is on the back of the gauge and there are no terminals for the two wire setup. It is quite likely that it is indeed an inductive system. The size seems to suggest that all current goes through it, and the meter would deflect according to what it feels. But I'd really recommend you research it further. You might check out a Mustang shop manual for '65 to see what the schematic says. My ammeter moves and stays just on + side when it is fully chaged. Yes, my dash pod is from a dead '66 coupe that I bought parts from 15 years ago or so. I had the Falcon style pod before which is wrapped up and on the shelf. On a shunt type system, just a sample of current is taken which shows the direction current is flowing so you get movement at the meter, sort of like a +/- voltmeter. It is simplistic but it works. If a system like mine shows no movement, it is almost always a dead alternator and/or VR if the wiring is good. I'm curious about this; let us know what you find out?
 

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Discussion Starter · #9 ·
So what I probably have here is a genuine '65 GT and/or deluxe interior instrument cluster. It does have the wood grain. The car itself is too early to have either. Wonder if its worth anything.
 

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A very old thread, yes, I know. Regardless, I feel that some additional info on the topic might be of use going forward...

It is quite likely that it is indeed an inductive system. The size seems to suggest that all current goes through it, and the meter would deflect according to what it feels. But I'd really recommend you research it further. You might check out a Mustang shop manual for '65 to see what the schematic says.
'65 shop manuals are, unfortunately, of no use in this particular case. The 5-gauge cluster wasn't introduced until the GT and Pony Interior showed up in mid-model-year. Those models received the inductive-style ammeter, which was replaced by the traditional stunt-type ammeter in '66 models. There may well have been a shop manual "addendum" published in early '65 to document this change, but I have yet to see/hear of one. Hence some of the mystery...


I suspect in 1965, there was a single wire that ran through the loop and connected to the other wire elsewhere. Exactly where, I haven't a clue. The circuit starts at the solenoid battery post, goes through the firewall, through the loop, back out through the firewall and connects to the alternator-battery harness, basically at the alternator junction.
There is a thick BLACK/YELLOW wire that passes through the loop and then immediately connects to a thick BLACK wire with a bullet connector (see my attached pic). I suspect that the black wire becomes black/yellow again at some point, but haven't been able to pinpoint exactly where.
 

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Do the 2 phillips screws as seen in your photo and referenced in the original post attach the gauge to the panel or do they serve some other purpose?
 

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There are a few options when installing a '66 cluster into a '65 when not also replacing the under-dash harness. One thing that must be done, regardless, is to snip out the socket for the single turn signal indicator bulb, and attach new sockets to each wire remaining for the new individual turn signal indicators. Now, for the ammeter.

Because the "Falcon" cluster used an alternator warning lamp, here are your choices....

1. Have the ammeter converted to a voltmeter and connect both the BLK/GRN and GRN/RED wires to the + side of the gauge and the other terminal to ground. You will then remove the WHI/BLK wire between the Voltage Regulator "S" terminal and the Alternator "STA" post, and move the GRN/RED wire in the VR plug from the "I" terminal to the "S" terminal.

2. Have the ammeter in the '66 Cluster replaced with a '65 ammeter and run a 10ga wire from the battery-side of the Starter Solenoid through the loop on the back of the gauge and back out to the "B" terminal on the back of the ignition switch. You will then remove the WHI/BLK wire between the Voltage Regulator "S" terminal and the Alternator "STA" post, and move the GRN/RED wire in the VR plug from the "I" terminal to the "S" terminal. Terminate the ends of the BLK/GRN and GRN/RED wires as they will no longer be used.

3. Use the '66 ammeter and connect as follows. Run a RED 16ga wire from the battery-side of the starter solenoid to the ammeter. This wire must be 89 inches long. Run a 21 inch YELLOW 16ga wire from a point in the BLK/YEL alternator output wire exactly 7 inches from the "BAT" post and splice/solder in place. Terminate the other end of the wire with a female bullet connector. Next, run a 89 inch YELLOW wire with a male bullet from the short YELLOW wire in to the ammeter. Now, you will then remove the WHI/BLK wire between the Voltage Regulator "S" terminal and the Alternator "STA" post, and move the GRN/RED wire in the VR plug from the "I" terminal to the "S" terminal. Lastly, terminate the ends of the BLK/GRN and GRN/RED wires as they will no longer be used.
 

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pretty sure I did bartl's #2 when I converted mine from '65 to '66 5 gauge system; works just fine...
 

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What Mid said. The wire goes through the metal loop. That said, you won't notice any difference if it is wired correctly or not! The gauge never moves...
Not True!! The 65 "loop" ammeter was the real thing, and worked great! It was the passive 66-73 types that work lousy unless you go to a LOT of trouble to clean ALL the connectors.

The main problem with this thread, old or not, is the OP's basic question is wrong. Y'see, he doesn't have a 66 instrument cluster, he has the real, and rare, 65.
 

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Do the 2 phillips screws as seen in your photo and referenced in the original post attach the gauge to the panel or do they serve some other purpose?
The screws merely hold the instrument in place.
 

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Not True!! The 65 "loop" ammeter was the real thing, and worked great! It was the passive 66-73 types that work lousy unless you go to a LOT of trouble to clean ALL the connectors.

The main problem with this thread, old or not, is the OP's basic question is wrong. Y'see, he doesn't have a 66 instrument cluster, he has the real, and rare, 65.
Not to hijack this thread but 22, i just switched to this bezel in my 65, i have the painless wiring kit so it had the option for the 65 bezel or the 66, my question is i have two 66 gauge clusters, one with the loop and one with the studs, i havent hooked up my ammeter yet so it doesnt work, but should i use the loop, or the studs, i want it to work properly.
 

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Not to hijack this thread but 22, i just switched to this bezel in my 65, i have the painless wiring kit so it had the option for the 65 bezel or the 66, my question is i have two 66 gauge clusters, one with the loop and one with the studs, i havent hooked up my ammeter yet so it doesnt work, but should i use the loop, or the studs, i want it to work properly.
Which type is "supported" by your Painless kit?
 

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Which type is "supported" by your Painless kit?
Thats true, i dont have a voltage regulator, the picture shows the studs so that is what i used. Was just reading that it doesnt work they well, ill know when i hook the ammeter up i guess.
 

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Thats true, i dont have a voltage regulator, the picture shows the studs so that is what i used. Was just reading that it doesnt work they well, ill know when i hook the ammeter up i guess.
Sounds like it uses the '66-style shunted ammeter.....

Make sure all the connections are nice and shiny. Chances are, more than not, that if you opened the cluster and looked at the gauge a bunch of corrosion would fall out. After 50 years most have pretty much had the radish.
 

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Not to hijack this thread but 22, i just switched to this bezel in my 65, i have the painless wiring kit so it had the option for the 65 bezel or the 66, my question is i have two 66 gauge clusters, one with the loop and one with the studs, i havent hooked up my ammeter yet so it doesnt work, but should i use the loop, or the studs, i want it to work properly.
You only have one 1966 cluster, the one with studs. The loop style was 65 only, the stud style was 66 only. In your place I would use the 65 cluster, and change the wiring harness to match it.
 
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