## **Connecting a Factory Amplifier via RCA and AMP-CON on SMARTY Trend Android Head Units (No Sound from Speakers)**

### Symptoms:

After installing the head unit, the system powers on, the interface works, tracks switch, and radio stations are found, but there is completely no sound coming from the vehicle's speakers (common for cars equipped with an external factory amplifier).

### Solution:

To transmit the audio signal and trigger the factory amplifier, you need to connect the **RCA** line-out plugs (male-to-female) on the head unit's adapter harness, tie together the **AMP-CON** control wires, and activate the amplifier profile in both the system settings and the CAN-bus configuration.

> **Important Note (Addressing a Common Concern):** Even if your factory car amplifier does not physically have (RCA) ports, the SMARTY Trend adapter harness includes paired RCA connectors (red and white). This is the standard method of connection between the main harness and the CAN-bus decoder box, which converts the line-level signal for the factory digital or analog amplifier bus. You do not need to look for an audio input port directly on the physical amplifier - simply plug the matching RCA connectors together inside the head unit's wiring bundle.

### Step-by-Step Setup and Connection:

**1.Connecting RCA Audio Channels (FL OUT / FR OUT):**

1. Locate the line-level audio outputs labeled **FL OUT** (white) and **FR OUT** (red) (or **AUDIO OUT L / R**) on the main wiring loom of the head unit.

2. Connect them to the corresponding RCA plugs coming from the power harness / CAN-bus adapter (red to red, white to white). *Verification:* The plugs are firmly pushed together all the way.

![](https://crm.smarty-trend.com/rails/active_storage/blobs/redirect/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaHBBaXd4IiwiZXhwIjpudWxsLCJwdXIiOiJibG9iX2lkIn19--2671df04870ef6238569bc939e2901cfe3c980ee/1.webp)

**2.Connecting the Amplifier Control Wire (AMP-CON):**

1. Locate the single wire (typically blue or blue-and-white, occasionally orange) labeled **AMP-C**, **AMP-CON**, or **AMP** on the harness coming out of the CAN-bus decoder or main power plug.

2. Connect it (via twist-and-tape or a crimp connector) to the matching **AMP CONT** control wire originating from the head unit to supply a +12V trigger signal. *Verification:* The contact is securely joined and insulated with no exposed copper strands.

![](https://crm.smarty-trend.com/rails/active_storage/blobs/redirect/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaHBBaTh4IiwiZXhwIjpudWxsLCJwdXIiOiJibG9iX2lkIn19--adeb74f39b3eea723e1415fcab2fad0e0c43658e/2.webp)

**3.Activating the Amplifier in Android and CAN-bus Settings:**

1. **CAN-bus Profile:** Go to the vehicle settings menu (Factory Settings → Model / CAN Selection) and ensure that your car's configuration is selected with the mandatory **"AMP"** (Amplifier) suffix.

2. **System Menu:** Open the head unit main menu: **Settings → Device → Sound → Amplifier Power** and toggle the switch to **ON**.

   *Verification:* After turning on the toggle and saving the CAN-bus profile, clean sound will start playing through the speakers.

![](https://crm.smarty-trend.com/rails/active_storage/blobs/redirect/eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaHBBakF4IiwiZXhwIjpudWxsLCJwdXIiOiJibG9iX2lkIn19--a9e4f27c24014b63dc8236de95cb8d2774501f90/3.webp)

### Keywords:

no sound android head unit, oem amplifier rca connection, amp-con wire, canbus amp settings, smarty trend troubleshooting.