How do I replace a default game file with a modded version?

I am creating a mod and would like to replace a currently existing file. I am editing the vampire interaction test for "compel for deep drink." I want to eliminate failure to drink. In the file testSet_Vampires_CanDrink I have deleted this portion:

<V t="buff">

<U n="buff">

<L n="blacklist">

<T>154327<!--buff_Vampire_UnwillingSnack--></T>

</L>

<E n="subject">TargetSim</E>

<V n="tooltip" t="enabled">

<T n="enabled">0x6B5429AE<!--This Sim recently resisted being drank from.--></T>

</V>

</U>

</V>

I want my vampire sims to never fail when attempting to drink from another sim. I exported my files and placed them in my mods folder and nothing has changed. Is there a way I can have this edited file override the original file? I want this new test set to be the one that is used by default. I thought that the mods folder is automatically put to priority and overrides things, however I am not sure, and it now doesn't appear to be the case. Maybe I am wrong. There could be something else wrong and I could be missing something.  Also, the first time I tried, I actually changed the tuning IDs as well, and edited the files accordingly. This didn't work, so I tried keeping them all the same as the defaults, to no avail.