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'73 AMP gauge conversion issue


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I am re-installing my dash and I have run into one small problem.

I got everything hooked up, but I am having a problem with the ammeter conversion. The AMP/Fuel gauge is from a 1976 280z. I used he following instructions in my swap:

"Basically you just disconnect the two fat White/Red wires (maybe just white?) from the back of the ammeter and re-connect them. Insulate the living daylights out of this connection, and not with just electrical tape. Use heat shrink, preferably the stuff with the glue on the inside.

Clean the contacts first. Bolt them together VERY tight.

Oh, and take a new 18 gauge wire from this same spliced connection and connect it to the + terminal of the voltmeter, and connect the negative terminal to ground. That's it."

Unfortunately the AMP gauge is only reading 4 volts. Here is a youtube video of the gauges operation.

I'm hoping someone can tell me what I did wrong or if my gauge is bad.



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Watched your video and the first thing I noticed was the white gauge faces. So it's been taken apart and re-assembled. At least the needle moves. There is an adjustment screw in the back of the voltmeter (not ammeter) that will set the starting point for the needle. I would guess that somebody turned that screw (a lot) when they were taking the gauge apart. I set mine to sit at 12.6 volts with the engine off by trial and error. Plug the gauge in and note the reading, unplug it and turn the screw, repeat.

I notice that your fuel gauge doesn't seem to work either. Gauge wiring is shown in the FSM's Body Electrical chapters.

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I put the gauge faces on myself, but I did not touch the adjuster screw. However, I do not know what may have happened to the gauge in the past so I will check the screw tomorrow. Is it okay to adjust that gauge with it still connected to the battery?

The fuel tank is empty so that may be why the fuel gauge looks like it's not working. Unless it's suppressed to wiggle like the voltmeter does.

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You might be able to use a meter to measure voltage at the plug to see if you have a gauge problem or some other problem.

I don't think that you can reach the adjustment with the gauge plugged in. Good luck on the fuel gauge, my tank has never been completely empty so I don't know how low the needle goes. I didn't think it went that low with power to it though. I wonder if you don't have the volt meter wire running through the fuel sender circuit. The resistance would lower the voltage.

Wire colors are lower on the page that the drawing came from, BE-35.


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Well I took the gauge out and wired it to the battery. Messed with the adjustment crew a little bit and it didn't change a thing. Looks like the Voltmeter is bad. Guess i'll have to buy another one. Thanks for the response! Hopefully this thread will end up helping someone in a situation similar situation to mine.

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