To connect it up, first ground the black wire at the ECU panel. You must be absolutely sure that this ground connection is good and do not be tempted to ground it anywhere but the same location as the ECU. If you ground it somewhere in the dash, a voltage offset can be introduced which will mess with the readings. Connect the red power wire from the gauge to the little power wire you left.
Connect one supply wire to the upper black wire. Before proceeding, you must decide whether you prefer 2000 or 2500 watts. a. For 2500 watt applications: Connect the remaining supply wires to both the black and red wires. b. For 2000 watt applications: Connect the remaining supply wire to the remaining black wire. Leave the red wire disconnected and cap loose end with an approved wire.
Connect the white wire to the inside lighting switch, which will illuminate the tachometer when the headlights are on. The red wire is for the ignition switch. Connect this red wire so that when the car is started the tachometer will begin operating. T-splice wire adapters allow for new wires to be spliced together with existing ones using pressure connectors that you squeeze around the.
There are two black wires attached to one brass screw and a red wire attached to the other brass screw. There appear to be two white (assume neutral) wires screwed together with a wire nut and a ground wire tucked away inside the junction box. This is an older house (circa 1967) and the wiring appears to be all over the place. I've successfully replaced some of the older outlets and switches.
The 4-wire connection is the new updated circuit. The only difference is the addition of an isolated ground wire separate from the neutral as mentioned earlier. A 4-wire cord consist of a 4 conductor cable with wires colored coded as Black (Hot), Red (Hot), White (Neutral) and Green (Ground). In a 4-wire circuit, the neutral and ground are.
Note that black is swapped for green, and yellow is swapped for red. Of course, it would also work if you consistently swapped the black and yellow wires the other way (black for red, yellow for green) but that is not the standard. Given that you have to be consistent between the two ends of the wire, you might as well follow the standard.
Two or three wires will be attached to the switch: an incoming hot wire, which is black; a return wire, which carries the load to the fixture and may be black, red, or any other color except green; and sometimes a grounding wire, which is green or bare copper.There may be other wires in the box, but you are only dealing with the ones connected directly to the switch.
Black would be hot, white would be hot, and green would be common. Four wire is usually two hots, a common and a chasis ground. Just make sure you don't connect one of the service hot wires to the.