Toyota is known for building robust vehicles, especially those based on the Land Cruiser chassis. This reputation extends to its luxury counterpart, the LX570. Aside from the pesky height-adjustable air suspension, the chassis is both rugged and capable. So when a 2008 LX570 rolled into the shop with a dead battery caused by several controls staying on, even with the key in the off position, it was a bit out of the ordinary.

The oddities didn’t stop there. As the technicians began duplicating the issues, they noticed that the radio, navigation, and clock remained on even with the key in the off position. Additionally, the door locks wouldn’t respond to the key fob, although the interior switches on the door cards worked just fine. Odd, to say the least. The problems persisted, even after the fob received a fresh set of batteries. It was time to check for DTCs and start tracing wires in search of the electrical gremlin haunting this overlanding hoss. Unfortunately, a quick scan revealed no stored or current DTC codes – so much for this being a simple repair. All signs pointed to an electrical wiring issue. Since tracing wires is a task most techs would rank below spending time with their ex-wife, the shop turned to ALLDATA’s Tech-Assist. A quick call pointed them to check for a voltage leak on the gray wire at F20 of the radio display and trace it back through the junction connector and inline connector to narrow down the fault.

Using the ALLDATA Repair OEM and interactive wiring diagrams, the technician pinpointed the wires under the center console. The next call to Tech-Assist guided them to trace the wire from J/C20 Pin 16 to the telephone system at PF3 Pin 22. Once disassembled, they discovered that the leakage from a dozen sodas and congealed candies had seeped into the wiring connector, causing significant corrosion. After cleaning up the mess and reconnecting everything, the system began working normally again.

While the technician could have spent countless hours checking continuity, chasing voltage draws, and unsheathing miles of wiring harness, the Tech-Assist line provided the guidance needed to zero in on the source.