Parasitic draw help

[trackmagic]

I’m chasing a parasitic draw / electrical backfeed issue on my 2007 Lexus LX 470 and have narrowed it down pretty significantly. With the RADIO fuse (56 in passenger foot panel) installed, multiple systems (nav screen and even the cigarette lighter circuit) stay powered with the key out, but everything behaves normally when that fuse is removed.

I’ve completely unplugged the nav ECU, the entire dash screen/climate control assembly, both rear headrest screens, and all modules under the seat (including amp/nav components), and the issue persists. I even replaced the ENTIRE ecu/fuse box assembly in drive footwell because I originally thought it was there.

The ACC circuit itself appears to function normally when isolated (cig outlets off with key out when RADIO fuse is removed), which suggests the ignition switch is not the cause.

At this point it seems like the RADIO circuit (constant B+) is somehow backfeeding into the ACC circuit through the dash harness, likely via a wiring fault or internal harness cross-connection rather than a module. I’m currently focusing on the center dash harness bundle but can’t see anything obvious.

Curious if anyone has seen a similar B+ to ACC backfeed in the 100-series wiring or knows of common failure points in that harness?

I am going INSANE

 

[rexington14]

Strange. Did this just start happening out of nowhere?

One other thing you can try unplugging is the 6 CD changer buried in the center console. That runs off the passenger RADIO fuse as well.

 

[trackmagic]

Strange. Did this just start happening out of nowhere?

One other thing you can try unplugging is the 6 CD changer buried in the center console. That runs off the passenger RADIO fuse as well.

Yes. This car is not a daily driver. I generally keep on tender, but recently noticed that the battery kept dying quickly. And then last week I noticed the nav/radio screen was on and the rear headrest tv’s. With the car sitting in the driveway.

I’ve noticed humidity in the car this winter from I think the sunroof drains so that’s what led me to thinking the driver side fuse box/ecu went bad and led to me replacing it. But as above… that didn’t solve.

I replaced alternator recently, but can’t see how that would tie into it.

I keep running in circles. I’ll unplug that 6disc and see.