Purchased additional remotes to use with the 402U but they do not program

I purchased additional remotes to use on a customer 202U and a 402U that I needed. The four that I used with the 202U programmed fine. The 2 that I am wanting to use with the 402U won’t program. Is there something that needs to be changed with the remote to make it work or are they defective?
Thank you! Other than this they work great!

The mode of transmission is different between the 202U and 402U. 202U mode has the red transmit light on constant. 402U mode has the red transmit light flashing. To change a transmitter in to 402U mode remove the battery from the remote and insert it again while holding down the C button. You will now be able to program for the 402U.

Also you can see video topic here Video - change remote battery & set TX134 dual-mode transmitter's working mode.

In above video, you will see how to change working mode, thanks.

Thank you very much. The remotes work perfectly. Thanks again for your quick response.

I have four TX134 remotes and two 402Us. All four remotes were working. I programmed all four for A, B on one 402 and C, D on the other. Then one stopped working. The little LED on the remote still blinks, but the 402U doesn’t recognize it. I even tried Erasing All Stored Transmitters on the 402U. (disconnect the power to the 402U, hold the PRG button down, connect the power, hold the PRG button down for the 5 second countdown). I could reprogram three of the 4 TX134s. They are still working. I will try this when I get a chance later today. I’m not sure what caused it to switch modes.

Per my previous post, I reprogrammed the TX134 remote to 402U mode and was able to make it work with the 402U. I don’t know how it changed from 402U mode to 202U mode.

Hello,

The 402U->202U mode switch is also on the video in link Video - change remote battery & set TX134 dual-mode transmitter's working mode.

For current TX134 version, if you don’t hold C during power up, then it naturally goes to 202u mode.

** This feature will change in future.

Also, then battery is low, then our remote will blink very quickly, in this case, remote is too weak to transmit functional signal, please change battery, thanks.