Hi, Not much help, but we both have the same year Ram 1500 with "which fuse to connect a fuse tap" in a 2019 Ram!
From what I have read online, access the fuse box under the steering column (remove two bolts and then unclip from the top of the panel) to reveal fuse box. Locate fuse 66 (lower right corner of fuse box).
Now MY WARNING!!!! I am NOT an auto electrician, so may be wrong..SOMEONE CORRECT ME if I am! If you are using the BlackVue Front/rear cams with the additional "Power magic battery" or even a 6.5 amp current draw; BE CAREFUL!!! The Fuse No .66 uses a 10amp fuse, (for factory Psgr window/sunroof power) the "battery pack" if connected to cigarette lighter socket draws 6.5 amps. If however you "hard wire to the fuse box" (and set selection switch on Power magic battery from cigarette to fuse box) it will draw up to 13.5AMPS!!! when charging this auxiliary battery!.
Having regard to the existing 10amp fuse you are now (my understanding) having to insert a 15 amp fuse (or another 10amp at least) into the fuse tap to support the BlackVue battery /hard wire power demand. Anyone who knows otherwise, Please chime in!!! You could be then "over drawing" in excess of the amperage of actual vehicle WIRING that goes to this fuse socket due to potential current draw 13.5amp + sunroof Amp draw + psgr window Amp Draw (how many amps? ). Resulting in Wiring damage/fire/damage to powered items/check engine lights/voided warranties?
If you have already experienced Check Engine light/errors, what will this type connection give, let alone potential over draw current on wiring not designed to piggy back such a substantial extra current draw? It probably won't blow either fuse as there won't be a short...but it could result in burning out the wiring/ overheating/melting or stopping items on this fuse wiring working altogether or a fire in the dash!
This type of camera wiring connection is an increasingly common question on these boards, so PLEASE, if someone can confirm or discount this claim I have made and provide a "safe and effective" wiring to fuse box it would both help and save future grief. I have read that members have had success with Fuse 66 using a fuse tap without issue, a single dashcam? Perhaps OK, but BlackVue or dual cams, I believe is a whole new ball of string. Thank you.