The most reliable way to permanently silence the cellular modem is to pull the relevant fuse. In the above case, this also disables the microphone, which I think is a positive. Unplugging the DCM entirely, however, seems to disable to right speaker, which is wired through the DCM for some reason.
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It seems like this is not enough:
https://www.tacomaworld.com/threads/simpler-solution-for-dis...
The most reliable way to permanently silence the cellular modem is to pull the relevant fuse. In the above case, this also disables the microphone, which I think is a positive. Unplugging the DCM entirely, however, seems to disable to right speaker, which is wired through the DCM for some reason.