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If your TV changes to an HDMI source without you choosing it, a connected device may be sending an HDMI-CEC command when it wakes, starts casting, or changes state. A device in standby can sometimes trigger the switch, too. The fix is usually to identify the source and adjust the TV’s CEC or automatic-input setting; the setting name and steps depend on the TV model and remote.
Why a TV can change inputs on its own
HDMI-CEC lets compatible devices send control commands to one another over HDMI. One common behavior is for the TV to switch to a device’s HDMI port when that device turns on. Google notes that casting to a CEC-supported TV from another source can switch the TV to the HDMI input used by a connected Google streaming device (Google Streaming Help).
The trigger is not necessarily a button press on the TV remote. LG says a connected device can signal an input change while in standby, and Samsung notes that a device may send a switching signal in error, even when it is not in use. These are documented possibilities, not proof that CEC explains every unexplained input change.
Identify the source before changing settings
- Note the input the TV switches to. Record the HDMI port or source name shown on screen.
- Check what happened just before the switch. Note whether a console, streaming box, soundbar, or other HDMI device woke, started casting, or changed state.
- Test one setting at a time. Start with the TV’s CEC or automatic-switch setting. If the behavior stops, you have a useful indication of the trigger. If possible, re-enable it and temporarily turn off CEC on the suspected external device to narrow down which device is sending the command.
- Update the suspected external device. Samsung advises checking for a firmware update when an external device appears to be sending an erroneous signal.
Menu behavior depends on the TV model, software version, and remote. Use the manufacturer’s instructions for the exact model or consult its manual rather than assuming one menu path works across a whole brand.
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Find the HDMI-CEC setting by brand
Manufacturers use different names for HDMI-CEC. These names can help you find the relevant control, but their presence does not guarantee that every model supports the same behavior.
- Samsung: Anynet+ (HDMI-CEC). Samsung says connected devices can tell the TV they have turned on, prompting it to switch to that source by default. Its instructions differ for infrared and Bluetooth smart remotes, so follow the procedure for your specific model and remote (Samsung Support).
- Sony: BRAVIA Sync or BRAVIA Link. Sony says turning BRAVIA Sync off can prevent automatic switching to the last input used by a connected HDMI-CEC device. Sony also documents “Auto Input Change (MHL)” for MHL devices; that setting is specific to MHL and should not be treated as a general fix for ordinary HDMI devices (Sony Support).
- LG: SIMPLINK. Check the model-specific instructions because paths differ by webOS generation and menu wording can vary (LG Support).
- Other names: Google lists Aquos Link (Sharp), HDMI-CEC (Hitachi), CE-Link and Regza Link (Toshiba), HDAVI Control, EZ-Sync and VIERA Link (Panasonic), EasyLink (Philips), and Realink for HDMI (Mitsubishi) (Google Streaming Help).
LG-specific steps for SIMPLINK and saved connection history
LG’s US troubleshooting article, published September 28, 2026, identifies SIMPLINK/HDMI-CEC, signals from connected devices in standby, and temporary saved connection information as possible causes. For a matching LG model, use its current support instructions to check these documented options:
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- Turn off SIMPLINK (HDMI-CEC). LG says this prevents connected devices such as consoles, soundbars, and streaming boxes from signaling the TV to change inputs.
- Turn off Quick Start+. LG includes this as a troubleshooting step for the issue.
- Delete saved connection history. LG documents clearing temporary connection information as another step to try.
LG’s paths vary by webOS generation and model. Use the support page or the TV manual to find the matching instructions rather than applying a path from another LG television.
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What changes when you turn CEC off?
Disabling CEC may stop a connected device from automatically switching the TV to its input, but it can also remove useful device control. Google describes CEC as a way to control HDMI devices with one remote. If you rely on that convenience, consider disabling CEC only on the suspected device, if its settings allow it, instead of turning it off across the whole TV setup.
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If the TV still switches inputs
If the problem continues after checking the relevant settings, updating the suspected device, and trying the model-specific steps, contact the TV manufacturer or a qualified technician. LG explicitly recommends those next steps when its troubleshooting does not resolve the issue. The cause may not be CEC, and the official guidance does not establish that this explanation covers every case.
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