Amp Gauge Conversion Question

[The70RT]

I had my cluster done and the amp gauge was converted to volts. There is only one terminal on the back. I just need to go through all the threads I guess. I read on here I need to hook the red and black leads together and run another wire from somewhere else to the gauge.

[Pete in NH]

Hi,

If that one terminal on the new voltmeter looks like it is insulated from the dash frame, try connecting  a 9 volt transistor radio battery + to the new stud, - to the dash frame. The new voltmeter should read. They may have grounded the new voltmeter internally, although it would be nice if they told you what they did.

With the ammeter now gone you will need to do some rewiring of the charging circuit and alternator output. What size alternator do you have on the car?

[The70RT]

Haven't got the motor in yet, I will have to look on the motor to see.

[The70RT]

So if I hook the black and red gauge wires together and run a another wire from my fuse box to the gauge is that all i need to do to the dash wiring? I see i need to do a couple mods on the engine harness but i just want the dash mod done so I can install the dash.

[b5blue]

I see a small green wire inside the cluster housing? Did you install the 12V gauge or have the entire cluster built? Perhaps it is wired inside as I see no provision outside?
  Yes with no ALT gauge to read amps the larger red and black get connected. 

[The70RT]

Neal the whole cluster was done by Instrument Specialties but they didn't give me any instructions what to do. So do you know if I hook these two together and run a wire to the volt gauge now it is all I need to do under the dash?

[b5blue]

I'm just spit balling but I "think" the VOLT gauge is wired inside the cluster. I know for certain the black lead must go to the red lead as that is power to recharge the battery. (The red goes to pin J bulkhead then to a fusible link to the starter solenoid. That has a battery cable on that stud also.)
You'd better call them to be sure.

[The70RT]

Yeah they converted the limiter so i think i'm good to go. I got all new wiring and will run the other wires under the hood when i get to that point.

[b5blue]

  Just did new harness on my 70, the headlight door relay up/down wires had to be switched (possibly because of the repop relay) and the column ignition switch to harness connector was very loose fitting? (I don't like the factory connection and did my own repair) M&M leaves no clip in the ACCESSORY slot for the output end of the fuse. I called them, they said "If you have anything that goes there you must send it to them for reproduction" they would not just supply a clip. They also said expect 12 weeks delay. 
  I strongly advise assume nothing at this point, new does not mean 100% perfection. Do your own quality control inspection to look for any flaws. I've found poorly crimped wires and light sockets that had the center contact not soldered correctly. Tug/pull/wiggle every possible wire/connection, use a bright flashlight to look inside every type connector from both sides very closely. Hopefully you waste an hour or so for finding nothing wrong but an oversight now could have you mystified and in tears later.   

[Pete in NH]

On connecting the heavy red and black wires together behind the dash- one of the reasons people go to using a voltmeter is to eliminate a high current circuit behind the dash board and running thorough the bulk head connector. Just connecting the two wires together only eliminates the ammeter but doesn't take full advantage of the voltmeter conversion.

If you're running a big alternator, one of the reasons to go to a voltmeter, you are still leaving the relatively light gauge wire and the bulk head connector pins in the path. I would suggest running a new heavier wire with a fuse or fusible link between the alternator output and 5/16" battery stud on the starter relay. The wire and fuse size would depend on the size of the alternator. The run a #8 gauge red wire from the 5/16" battery stud through a 50 amp Maxi-Fuse and connect the end of this wire to the black wire that used to go to the ammeter. This arrangement will take full advantage of your voltmeter conversion and get the bulk head connector and high current behind the dash out of the way.

[The70RT]

I agree Neal, every repo piece I bought needs tweaking it seems. Yeah Pete thanks, I did a search where you posted that, i will do that