What wire does the D+ terminal of a car alternator connect to?

[Joanne]

D+ terminal refers to the neutral point, which connects to the charging indicator light, voltage regulator housing, and the positive power supply of the alternator regulator. B+ or B or +: The positive output terminal of the alternator, which is the rectified positive output from the alternator stator. It connects to the positive terminal of the battery, the voltage regulator, and the vehicle's electrical loads. For alternators without a battery, the B+ terminal directly connects to the air conditioning system. F+ or F or D: The field terminal, which connects to the 'field' terminal of the voltage regulator to supply excitation current to the alternator rotor. B- or E: The rectified negative output from the alternator stator, which is connected to the negative terminal of the battery and the negative terminal of the voltage regulator, usually directly grounded. N or P or W or R or L: The neutral point output terminal of the alternator, with an output voltage half of B+. It connects to the tachometer, charging indicator light, relays, etc.

[LaBriella]

I just repaired my old Ford last month. The generator's D+ terminal is actually connected to the charge indicator light, which is the battery symbol light on the dashboard. When you turn on the ignition switch but don't start the engine, this light comes on; after starting, the light goes off once the generator is producing electricity. When I disassembled the generator, I saw that the D+ needs to connect two wires: one goes to the charge indicator light, and the other connects to the field coil through the voltage regulator. If it's wired incorrectly or has poor contact, the charge indicator light will either not light up or stay on constantly, and in severe cases, it can burn out the voltage regulator. When wiring, be careful not to short it to the casing—it's more reliable to check the resistance with a multimeter. Last time, I didn't pay attention to this, and the battery was drained in just three days.

[EllaFitz]

After twenty years of repairing cars, I've discovered that there's a lot to the D+ terminal wiring of the alternator. It primarily connects to the charging indicator light circuit, and in some vehicles, it also directly links to the voltage regulator. The standard practice is to use a blue or yellow wire to connect to the charging indicator terminal behind the combination meter, ensuring it's also connected to the voltage regulator's field circuit. There are three common mistakes when wiring this: first, the wiring harness aging and breaking; second, terminal oxidation leading to poor contact; and third, mistakenly connecting it to the alternator's output terminal. Recently, a Touareg had intermittent power generation issues due to a loose D+ terminal, causing it to break down halfway. When wiring, it's best to disconnect the battery's negative terminal first to avoid short circuits and sparks.

[XavierFitz]

I've studied the D+ terminal when modifying my car's electrical system. Its core function is to control the charging indicator light while also providing initial excitation to the alternator. In terms of wiring connections, the D+ should be connected to the dashboard's charging indicator light, then routed back to the alternator through the ignition switch. In actual operation, you need to use a multimeter to confirm: when the key is turned to the ON position, the D+ should show 0.5-1 volt; after starting, the voltage should rise to 12 volts before the indicator light turns off. The most frustrating issue is oxidized wiring in older cars - last time I had to replace three wires to solve the problem of the light flickering on and off.