notothisrealm Posted September 6, 2015 Share Posted September 6, 2015 I know this topic has been discussed before, but i can't find pictures or a wiring diagram explaining how to do the swap. I read that i should splice the two white wires, one with a red stripe together and connect those to the power wire on the gauge. Is this true?? Any help would be appreciated. Quote Link to comment Share on other sites More sharing options...
z240 Posted September 7, 2015 Share Posted September 7, 2015 (edited) Yup, that's right! EZPZ. Connect them with a short 5mm or 10-24 bolt and nut and insulate VERY well. Use a big piece of shrink tubing ideally. Connect in a short piece of 18 guage red wire with ring terminal and connect that to the voltmeter. There is also a ground wire on the volt guage. Lots of plain black wires in the harness in with the guages that you can use. Tricky part is finding the volt fuel gauge from a 280 and swapping its guts into the 240 Amp/Fuel housing. Actually its simple. The swap, not the finding... Edited September 7, 2015 by z240 Quote Link to comment Share on other sites More sharing options...
notothisrealm Posted September 8, 2015 Author Share Posted September 8, 2015 Okay, this is the 280z gauge. I know the wires i circled in black are for the fuel tank. Im thinking the thick white wires are supposed to go to one of the wires in the red circle. Question is which one?? Quote Link to comment Share on other sites More sharing options...
z240 Posted September 8, 2015 Share Posted September 8, 2015 (edited) Ah good, you have a gauge. Easy to tell which of the two black wires is for +12 and which is for ground. Just hook them up to a battery, first one way then the other. When the gauge reads +12, you have it right. Then hook up that black to the thick white old ammeter wires. You may have to connect the other black wire to ground. Ah, just went and looked at a gauge. There is one black wire with a red band around it need the connector. Dollars to donuts that's the +12 wire. I'll go do the battery test myself to confirm Edited September 8, 2015 by z240 Quote Link to comment Share on other sites More sharing options...
z240 Posted September 8, 2015 Share Posted September 8, 2015 sure enough, black wire with red band = +12, other black is ground. The pin is the one top left, looking at the gauge connector with the pins facing you. Quote Link to comment Share on other sites More sharing options...
notothisrealm Posted September 8, 2015 Author Share Posted September 8, 2015 Awesome, thanks for the input. Im gonna try it out right now. Ill keep you posted. Quote Link to comment Share on other sites More sharing options...
notothisrealm Posted September 8, 2015 Author Share Posted September 8, 2015 Ok, the blue and green are for the charge light. How would those be wired up? Quote Link to comment Share on other sites More sharing options...
notothisrealm Posted September 8, 2015 Author Share Posted September 8, 2015 And i just had another concern. Wouldn't i need something between the thick white wires and the thinner wires to the gauge? Quote Link to comment Share on other sites More sharing options...
z240 Posted September 8, 2015 Share Posted September 8, 2015 The charge light is a nice to have, but knowing the voltage is all you need to determine if you are charging or discharging. A fully charged battery is at 12.6-12.8 volts, your alternator should be able to produce 13.8 - 14.2 volts, you'll see it when you first fire up what's "normal" for your alternator. Then if the voltage falls below 12.8, you're discharging. Anything above 12.8 and you're charging. That's the beauty of the voltmeter. Running voltage PLUS knowledge of charge/dis-charge. As to connecting a thin wire to the splice where the two white connect, just tuck the bare end of your new thin wire under the nut/washer you're using to connect the white wire ring terminals. Wrap it clockwise, the same direction as you tighten the nut. Better yet, crimp a ring terminal on the end of the thin wire. Chose a size with the same hole size as the white wire ring terminal and join them all with the same bolt. Quote Link to comment Share on other sites More sharing options...
notothisrealm Posted September 8, 2015 Author Share Posted September 8, 2015 I got it, thanks for the help!! I left the charge light disconnected. Im guessing the gauge is always on, even with the car off? And bow i have to figure out why my fuel gauge isn't reading. It wasn't working with the old gauge either. I have fuel in the car. Any guesses on that?? Quote Link to comment Share on other sites More sharing options...
mtnickel Posted September 8, 2015 Share Posted September 8, 2015 I had my sending wires mixed at the tank and it didn't read correct. I guess one wire references differently and it's not just a straight potentiometer. Could check that. Quote Link to comment Share on other sites More sharing options...
notothisrealm Posted September 8, 2015 Author Share Posted September 8, 2015 Hmmm, well the gauge was working before. Little by little the gauge stopped working. Quote Link to comment Share on other sites More sharing options...
wrcbonk Posted September 9, 2015 Share Posted September 9, 2015 As Mtnickel said check the level sender connections at the tank, they are poorly designed connectors and notorious for slipping off. Make sure the ends are free of grit with contact cleaner. Quote Link to comment Share on other sites More sharing options...
notothisrealm Posted September 12, 2015 Author Share Posted September 12, 2015 Alright, checked the yellow and black wire coming from the tank and they are connected, and its odd. Never seen connectors like the two that are on the tank. Anyway Im not getting any power coming from the terminal on the tank. Shouldn't it be sending some kind of signal to the yellow wire? Quote Link to comment Share on other sites More sharing options...
beermanpete Posted September 12, 2015 Share Posted September 12, 2015 (edited) Yes, you should be able to measure a voltage on the yellow wire when it is disconnected and the ignition switch is in the on position. The usual test is to breifly ground the yellow wire. When working correctly, the fuel gauge should go to full (past it more likely) rather quickly. Have a helper watch the gauge so you don't have to leave it grounded very long as it is hard on the meter. Just a brief touch should do to see any movement of the meter needle. Edited September 12, 2015 by beermanpete Quote Link to comment Share on other sites More sharing options...
notothisrealm Posted September 12, 2015 Author Share Posted September 12, 2015 Ah, cool!!! Thank you! Quote Link to comment Share on other sites More sharing options...
Kbhead Posted February 15, 2019 Share Posted February 15, 2019 On 9/8/2015 at 10:32 AM, notothisrealm said: Ok, the blue and green are for the charge light. How would those be wired up? Quote Link to comment Share on other sites More sharing options...
Kbhead Posted February 15, 2019 Share Posted February 15, 2019 (edited) Hello, reading through your post, I didn't see an answer to your question. I think the green wire goes to +12 volt when ignition is on? But where does the blue wire go? Thank you, Edited February 16, 2019 by Kbhead Quote Link to comment Share on other sites More sharing options...
Kbhead Posted February 24, 2019 Share Posted February 24, 2019 Hello, Can anyone tell me where the Blue and Green wires go to? I'm assuming both can go to +12v when ignition is turned on. thanks Quote Link to comment Share on other sites More sharing options...
Milkman Posted January 24, 2022 Share Posted January 24, 2022 Hello, did you ever find out where the wires to the charging light go. I'm doing the 280Z 60 amp alt. upgrade with the jumper plug , which has a diode in in , that plugs in to the voltage regulator connector. a lot of bits and piecing together of info. This shouldn't be that hard. I think the charge light should definitely be working. If you know can you let me know. I'm am going to make this work some how. Thanks, Bill. Quote Link to comment Share on other sites More sharing options...
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