"Body ECU" , BCM, Back-Up Lights Relay

I am trying to find Circuit board Diagrams for "Body ECU" (Toyota's Term) I've recently had all my reverse lights lights go out. Digging through the book and wiring diagrams and that I've dealt with some of this circuit before I'm 95% sure it's going to be the "Back-Up Lights Relay" which shouldn't take long to confirm. But from my understanding it's built into the "Body ECU" so I'm trying to find a "Circuit board diagram" for it so when I get to that point I can hopefully replace the relay on the board. A new "Body ECU" is $1,200 , particularly looking for "Floor shift" (Console shift) as the wiring is different with a "Column shift".

07 Crewmax , Floor shift, 5.7L, SR5, 4x4

 

Try here...https://www.tundras.com/threads/ultimate-tundra-wiring-diagrams-collection.81448/

 

Its pretty rare for the relay to fail but not impossible. Have you verified all the fuses shown at the top of this wiring diagram are good.

The back up light relay is J52 and is not integrated in the body control module however you will see the wiring diagram shows only the column shift *1 trucks have the back up light relay. If you are floor shift trace the *2 wires only.

 

To add to what Jeff stated - for Floor shift, if you were to "erase" the wires that have a (*1) next to them, you would see that the Reverse Lights are powered directly through the Park/Neutral position switch from the 10A BK/UP LP fuse and then directly out (through a long route with lots of junction connectors) to the reverse lamps. The floor shift trucks do not use the 7.5A LH-IG fuse, the 7.5A ACC fuse, the ignition diode, OR the Back-up Light Relay as part of the Back-up lights

 

Okay professional procrastinator here spent two hours today troubleshooting the reverse lights and learned some secretes of the gremlins. Also in my haste to make sure I take 20 pictures for the write up I completely forgot to take pics till the very end.

I first started by removing the tail light housings and checking both bulbs with a Autel power probe set to "circuit test mode" (Just needed to be 200% sure) both lit up when tested. I then used my multimeter and tested both sides for ground and it came back good at .5ohms, I moved to test for power at the plugs when it goes into reverse and had 2.75 volts (not enough volts to power any of the two bulbs or two led bumper lights) followed the harness up the passenger side into the engine compartment to the harness junction block upon inspecting no color wires match the "wiring diagram" so I crawled back under the rear where the reverse lights pig tail connected to the body harness found the "red wire with a blue stripe" double checked using a T needle back probe to ohms test and found it goes to a "blue wire with red stripe" (reversed color scheme) all the way up to harness junction block. Then used a coil/spare wire to run from the front to the back of vehicle so I could run ohms test to double check the wire was correct it came back good which at this point I then used a power probe to shoot 12v's to check for illumination which it illuminated. I then reconnected the harness and back probed the connector and had a 0 volts reading which then I went back to bulb socket to check voltage and had a 0 volts reading which earlier I had 2.75 volts at. Went to check power at the fuse on both sides with readings of 12.5 volts to no surprise. Redundantly I checked for power at the Park neutral switch which I couldn't get any probe or reading to cooperate so I had to settle with 100% sure instead of 200% since the Gear Position lights function and read correctly (which they wouldn't if there was no power or bad switch). So I followed the wires coming off the harness junction block into the cab which is a light blue solid wire where I toke the passenger side kick panel off and there it was the smoking gun. A fried crappy butt connector and 1" of burnt wire that started melting other wires from the aftermarket reverse camera that never worked since I owned the Tundra. I Cut out the bad fried wire and put in about 1.5"s of good wire and left the reverse cam trigger wire out of it (not hooked in) and what do you know reverse lights now work.