AVH-X7800BT Car Stereo System

Hello,

The handbrake contact is there to prohibit the video from operating while driving (illegal).

Excerpt from the manual

The manual: https://fc.darty.com/notices/DOCUMENTATION/2016/04/4197267_NOTCOMP.pdf

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It is very difficult to catch a black cat in a dark room.
Especially when it is not there...

I do not judge, I respond to your sentence:
"I would like to connect the green wire of the parking brake without putting it on the brake connector unless there is no choice,"

just reminding you of the reason why the green wire must not be connected directly to ground but to a contact that allows detecting a stationary vehicle.

You connected the green wire to the black wire... Which black wire?

You then say that your car stereo no longer starts up... even when reversing?

Check that there isn't a fuse that has overheated...

If that's not the case, there is in the car stereo a system that detects a change of state from presence of voltage to absence and vice versa

Very difficult to catch a black cat in a dark room.
Especially when it is not there...

Hello Rimek94,

To use all the features of your Pioneer AVH-X7800BT car stereo, the green wire (parking brake wire) must be properly connected or "bypassed" so that the stereo interprets that the handbrake is engaged. If you connect it directly to ground (black wire), it may initially work, but the built-in security system in the head unit will likely detect the tampering after a restart or an update.

Here are points to consider to resolve your issue:

1. Why can't the green wire be directly grounded?

• Pioneer, like many manufacturers, includes a security system that verifies a legitimate handbrake connection. This system can detect attempts at short circuits or other non-conforming manipulations.
• Once the system is triggered, certain features of the car stereo, such as video playback, are blocked.

2. Recommended solution: Relay or signal bypass

If you want to bypass this restriction without using the handbrake, you can use a relay or signal bypass. Here is a safe and commonly used method:

• Purchase a simple 12V relay or a suitable bypass module for car stereos.
• Connect the relay as follows:
  • Green wire to the relay.
  • Relay power to a switched 12V source (such as the ignition wire).
  • Ground to the black wire.
  • Configure the relay to send a simulated signal to the green wire.

This process simulates the engagement and disengagement of the handbrake, which will unlock the greyed-out features.

3. Check the current connections

In your case, if you have already connected the green wire directly to ground:

• Disconnect the green wire from ground (black wire).
• Restart the head unit to reset the system.
• If the problem persists (such as the screen no longer opening), it may be that:
  • The system detected a overload or a short circuit.
  • A safety mode has been activated.

4. Check power supply and fuse

If the retractable screen no longer opens:

• Make sure the main fuse of the head unit is not blown.
• Also check that the power connector provides a stable current (use a multimeter to check 12V on the red and yellow wires).

5. Resetting the head unit

• Consult the manual to perform a full reset of the head unit.
• Disconnect the head unit from the harness for a few minutes, then reconnect it to attempt to reset the circuits.