Fuse boxes detailed information. 2022 RX450h

[Lesfac]

I have just fitted a dashcam to my 2022 RX450h. I have used the 12volt socket (cigarette lighter socket) to get the power. This means some of the dashcams capabilities do not work. For example recording after a bump when parked. For this reason I have been looking at hard wiring kits to get the increased functionality.

The hard wiring kits are installed in the fuse box of the car and I have been searching for information on the layout and assignment of the fuses in the fuse boxes so that I can plan where to fit the hard wire kit.

The only manual I can access is the on line manual that I downloaded and this only gives the location of the fuse boxes with no further detail on the fuses.

Can anyone tell me if there is any information available on the fusebox layout and function for each fuse? I imagine Lexus must have this printed somewhere?

[Herbie]

If you can't find the info you need I highly recommend buying a multimeter. As you can see here you don't need to spend a lot of money on one but they are invaluable for sorting out electrical problems.

All you need do is to use the meter to find one fuse that is permanently 'live' and has 12V on it all the time. Then find a second fuse that is only live and only has 12V on it when the car is in ACC (or is it READY mode, I can't remember). Finally you'll need a good earthing/grounding point (any unpainted and clean screw/nut/bolt/bracket will do).

It doesn't matter what the fuse you're tapping into is rated at because the 'piggy-back add-a-fuse' (one of these things) you'll use for the camera will have it's own fuse.

[Lesfac]

Thanks for the reply Herbie. I do have a multi meter. I have watched installation videos on YouTube and most tell you to look for "non critical" fuses. I agree with you because if it works, it works. But I would be inclined to use "less important" fuses.

[ColinBarber]

16 minutes ago, Lesfac said:

But I would be inclined to use "less important" fuses.

Most of the critical ones (ECU, ABS, Traction control etc) would be in the engine bay so you won't be near them, just don't use ones related to SRS or A/BAG. The fuse box cover will have all the fuses listed on the inside (although in a cryptic form such as S/ROOF, OBD or FOG RR).

You will also probably find that the fuse box cover cannot be replaced with the piggyback fuse in place - so keep it safe somewhere.