Circuit/System Description
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
For an overview of the component/system, refer to : Horns System Description and Operation
| Circuit | Description |
|---|---|
| B+ - Relay Coil | Supplied from a fuse. |
| B+ - Relay Switch | Supplied from a fuse. |
| Signal - S33 Horn Switch | The control module input circuit has an internal resistance connected to 12 V. |
| Control - P13 Horn Assembly | The output circuit is switched to 12 V to activate the component. |
| Control - Relay Coil | The output circuit is switched to ground to activate the component. |
| Ground - S33 Horn Switch | Chassis Ground |
| Ground - P13 Horn Assembly | Chassis Ground |
| Component | Description |
|---|---|
| P13 Horn Assembly | The horn has an electromagnet which pulls a diaphragm inwards and simultaneously opens a contact which interrupts the current through the magnet. When the diaphragm springs back, the contact is closed and the cycle starts over. The vibration of the diaphragm produces the sound. |
| S33 Horn Switch | The switch has a normally open contact. When the switch is activated, the signal circuit to the control module is grounded. |
| K9 Body Control Module | The module controls various vehicle functions like lighting, central door locking, power windows, etc. |
| X50A Fuse Block - Underhood | The fuse block houses various fuses and relays. |