Which is the constant power, ACC or VCC?

[KennedyMarie]

VCC is the constant power wire. Relevant introductions are as follows: 1. VCC wire: Test method using a 12V car bulb - Generally, the black wire is the negative pole. Connect one end of the bulb to the black wire. If the other end is connected to the VCC wire (the bulb stays constantly lit without key control), it's the VCC wire; if the other end is connected to the ACC wire (the bulb turns on/off with key control), it's the ACC wire. 2. ACC wire: Trace along the ACC switch path. You can use one end of a test pen to touch metal and the pointed end to probe the ignition wires under the steering wheel. First turn on the left turn signal, then when probing the correct wire, the small light on the test pen will flash synchronously.