Instrument Cluster Removal

[RedFish]

No you didn't trace it back to a flasher. Explanation starting from a little deeper into wiring... All wires are hot wires. There's a positive side and negitive side to a current path/circle. So the positive side of your battery and your amp gauge have a red wire. The negitive side of you battery and your amp gauge have a black wire. The black wire on the amp gauge is everything on the negitive side of the gauge and current path but it is just as hot as the red wire.
This black wire goes to a weld splice hidden under tape. The branches go to headlight switch, fuse box, ignition switch, etc...
Another black wire ( hot at switch on ) leaves the ignition switch to another weld splice. These branches go to a flasher module, your inst' panel, etc...
I hope you can now read your schematic again with more understanding. If not, The 12 volts to your inst' voltage regulator came from the ign' switch on a black wire.
We all agree that these black wires should have been pink, or red with a tracer, or black with a tracer, and that is found in later models. That isn't how it was done early on. The truth is, Those who are trained in electrical don't need different wire colors at all. The different wire colors are only to dumb it down for the novice ( we all ). Mfgr's continued to dumb it down more and more over the years.

 

[CaptRon]

No you didn't trace it back to a flasher. Explanation starting from a little deeper into wiring... All wires are hot wires. There's a positive side and negative side to a current path/circle. So the positive side of your battery and your amp gauge have a red wire. The negative side of you battery and your amp gauge have a black wire. The black wire on the amp gauge is everything on the negative side of the gauge and current path but it is just as hot as the red wire.

So if that wire is negative does it not still attach to ground at some point? Also in the attached pic I have the volt controller and condensor or what appears to be a condensor plugged back into the panel the way I found it. Someone had spliced in a red wire about 2' long with a round pin connector on the end. it's got the male end connected but no wire coming out of it. I'm guess that pulled out. I haven't spent a lot of time trying to find the wire that may have been crimped into it.
Would it be plausible to assume that this red wire was connected to complete the circuit after the strip on the board broke or fried? If so would you recommend using that setup since it's already created or one like it? I've already ordered a direct replacement but electronic controller so if this is a decent compromise I might want to go that route???

This black wire goes to a weld splice hidden under tape. The branches go to headlight switch, fuse box, ignition switch, etc...
Another black wire ( hot at switch on ) leaves the ignition switch to another weld splice. These branches go to a flasher module, your inst' panel, etc...
I hope you can now read your schematic again with more understanding. If not, The 12 volts to your inst' voltage regulator came from the ign' switch on a black wire.
We all agree that these black wires should have been pink, or red with a tracer, or black with a tracer, and that is found in later models. That isn't how it was done early on. The truth is, Those who are trained in electrical don't need different wire colors at all. The different wire colors are only to dumb it down for the novice ( we all ). Mfgr's continued to dumb it down more and more over the years.

 

[RedFish]

We can consider ground and negative the same thing since there isn't a neutral/earth/ground. Even if you look at it this way... positive is positive until some current is consumed.... where in a light bulb does positive end and negative begin? Where the electrode meets the filament? That wouldn't apply at the amp gauge since it doesn't consume current. It simply reacts to current flow. If those 2 wires weren't different colors, they would surely get hooked up reverse, and the instrument would react in reverse.
Lets just be thankful there are different colors. Imagine what if all wire casings were black? We would all need more knowledge to simply hook up a battery.
If your added red wire is tied to the same source black wire that would work. I can't know where someone might have attached it before. Does look like their crimped terminal pulled off from wherever the put it.
It was spliced into the lead of the noise suppression capasitor. If you cut into that little lead you will find that isn't a copper wire. Its steel or something ( not sure really ). Why it isn't copper or what difference this makes goes beyond my electrical knowledge.
A solid state regulator doesn't make electrical noise so the noise cap' is no longer required. You would have to ask whoever supplied the solid state regulator package, "Does the noise cap' make a difference?" I say this because some of the fancier solid state units have built in fault sensing with LEDs that flash fault codes. It may see the noise cap" as a fault. Sorry I don't have every answer.
One more point to mention... the original limiter is/was supplied from the ignition switch. The only fusible link, other than the main one out at the bulkhead, is/was that narrow spot in the copper trace. You have opportunity to add a inline fuse holder before your solid state regulator.
Necessary? If the OEM engineers felt there should be a point of safe failure somewhere, I wont argue with that.
For what its worth... The rally inst' panel has it voltage limiter housed inside the fuel gauge. Inside that gauge is also a tiny length of wire that serves the same purpose... A engineered point of safe failure. Better than frying wires back to harness connectors or all the way back to the ignition switch connector in all cases.
We have seen dash harnesses burned from here to yonder but that isn't common. Their engineers did go to some effort to control the damage caused by the possible/somewhat predictable faults.

 

[CaptRon]

We can consider ground and negative the same thing since there isn't a neutral/earth/ground. Even if you look at it this way... positive is positive until some current is consumed.... where in a light bulb does positive end and negative begin? Where the electrode meets the filament? That wouldn't apply at the amp gauge since it doesn't consume current. It simply reacts to current flow. If those 2 wires weren't different colors, they would surely get hooked up reverse, and the instrument would react in reverse.
Lets just be thankful there are different colors. Imagine what if all wire casings were black? We would all need more knowledge to simply hook up a battery.
If your added red wire is tied to the same source black wire that would work. I can't know where someone might have attached it before. Does look like their crimped terminal pulled off from wherever the put it.
It was spliced into the lead of the noise suppression capasitor. If you cut into that little lead you will find that isn't a copper wire. Its steel or something ( not sure really ). Why it isn't copper or what difference this makes goes beyond my electrical knowledge.
A solid state regulator doesn't make electrical noise so the noise cap' is no longer required. You would have to ask whoever supplied the solid state regulator package, "Does the noise cap' make a difference?" I say this because some of the fancier solid state units have built in fault sensing with LEDs that flash fault codes. It may see the noise cap" as a fault. Sorry I don't have every answer.
One more point to mention... the original limiter is/was supplied from the ignition switch. The only fusible link, other than the main one out at the bulkhead, is/was that narrow spot in the copper trace. You have opportunity to add a inline fuse holder before your solid state regulator.
Necessary? If the OEM engineers felt there should be a point of safe failure somewhere, I wont argue with that.
For what its worth... The rally inst' panel has it voltage limiter housed inside the fuel gauge. Inside that gauge is also a tiny length of wire that serves the same purpose... A engineered point of safe failure. Better than frying wires back to harness connectors or all the way back to the ignition switch connector in all cases.
We have seen dash harnesses burned from here to yonder but that isn't common. Their engineers did go to some effort to control the damage caused by the possible/somewhat predictable faults.

Thanks for your help! Every answer is appreciated!
I have the IVR4 shown here.
RTE limiter - rte

 

[RedFish]

Their info is all about its output side,, gauge operation and protection. They don't address the input side other than the input voltage range. We'll assume their unit does not sense if the noise cap' is present on the input side or not. It isn't required though.
So... Use what you have on the cap's lead to make the 12 volt input ( with or without a inline fuse ).

 

[CaptRon]

Their info is all about its output side,, gauge operation and protection. They don't address the input side other than the input voltage range. We'll assume their unit does not sense if the noise cap' is present on the input side or not. It isn't required though.
So... Use what you have on the cap's lead to make the 12 volt input ( with or without a inline fuse ).

Thanks, now I just need to figure out where that red wire was or should be connected. I guess it's time to lay on the floorboard with a flashlight.
all future connections will be soldered unless there is a good reason not to. It's a freakin rats nest under that dash!!!

 

[RedFish]

There is a weld splice somewhere buried under tape. Follow the other wires from that inst' panel connector or follow the wires away from the ignition switch.
Actually there are 2 weld splices. The one with larger gauge black wires is the one after the amp gauge, feeding headlight switch, ignition switch, fuse box, etc...
The black wire you're looking for comes from the other weld splice with smaller or mixed large and small gauge black wires ( I can't see the diagram ).

 

[CaptRon]

There is a weld splice somewhere buried under tape. Follow the other wires from that inst' panel connector or follow the wires away from the ignition switch.
Actually there are 2 weld splices. The one with larger gauge black wires is the one after the amp gauge, feeding headlight switch, ignition switch, fuse box, etc...
The black wire you're looking for comes from the other weld splice with smaller or mixed large and small gauge black wires ( I can't see the diagram ).

Thanks again!!
If I'm lucky this will bring my fuel and Temp gauge back to life!!