my remote just stopped working with the tv, won't turn it on or change channels, but the red light on the remote blinks.

Diagnosis

The TCL 43S446 S-Class utilizes a hybrid remote system. While basic power and volume commands often rely on Infrared (IR), the voice functionality and advanced navigation utilize a Bluetooth Low Energy (BLE) RF connection. When the red light blinks but the TV does not respond, it indicates that the remote is powered and attempting to send a signal, but the "handshake" between the remote's RF transmitter and the TV's internal receiver has been severed. This typically occurs after a power surge, a firmware update that resets the Bluetooth cache, or when the remote has been inactive for a long period. Because the red light is blinking, we know the batteries are providing voltage, but the lack of response suggests the TV no longer recognizes the remote's unique hardware ID. You can confirm this by attempting to use the physical power button on the underside of the TV bezel; if the TV turns on manually but the remote still fails, the issue is strictly a pairing failure.

How to Fix It

To restore the connection, you must force the remote back into pairing mode to re-establish the RF bond. Follow these precise steps:

1. Turn the TV on manually using the physical button located on the bottom edge of the frame.
2. Remove the battery cover from the back of the remote.
3. Press and hold the 'OK' button and the 'Back' button (the arrow pointing left) simultaneously for exactly 5 seconds.
4. Watch the LED indicator at the top of the remote. It should transition from a blinking red to a flashing green light.
5. Once the green light flashes, release the buttons and immediately press the 'Play/Pause' button.
6. Wait 10-15 seconds. A notification should appear on the top right of the TV screen confirming that the "Remote is paired."
7. Test the voice button to ensure the BLE connection is fully active.

If That Didn't Work

• Perform a Hard Power Cycle: Unplug the TV from the wall outlet and remove all power cables. Hold the physical power button on the TV chassis for 30 seconds to drain the capacitors. Plug it back in and attempt the pairing sequence again. This clears the cached Bluetooth pairing list.
• Battery Voltage Check: Even if the red light blinks, the voltage may be too low to sustain a Bluetooth RF transmission (which requires more power than a simple LED blink). Replace the existing batteries with two brand new AA alkaline batteries. Avoid using rechargeable NiMH batteries, as their lower voltage (1.2V vs 1.5V) can cause intermittent RF drops on S-Class models.
• IR Obstruction Test: If the remote is not a voice-enabled model, it relies solely on IR. Ensure there are no soundbars or decorations blocking the bottom-center of the TV frame where the IR receiver is located. Use a smartphone camera to look at the front of the remote while pressing a button; if you don't see a purple flicker through the camera lens, the remote hardware is dead.
• TCL Roku App Bridge: Download the Roku app on your smartphone and ensure it is on the same Wi-Fi network as the TV. Use the app's virtual remote to navigate to Settings > System > Advanced system settings > Reset > Reset remote. This wipes the TV's remote memory, allowing you to start the pairing process from scratch.

Heads Up

• Avoid using "Universal" replacement remotes if you want to keep voice search functionality; only official TCL RF remotes support the BLE voice bridge.
• Keep the remote away from high-interference devices like microwave ovens or powerful wireless routers, as these can disrupt the 2.4GHz signal used for pairing.
• If you frequently experience pairing drops, check for a system update in the settings menu, as TCL often releases patches to improve BLE stability.
• Never use leaking or corroded batteries, as the S-Class remote terminals are highly susceptible to oxidation, which can permanently kill the RF transmitter.