Several months ago while driving a 2006 GX the radio died and the fan quit and the clock went dark and so did the dash cluster and there was a noticeable and quick loss of power. I pulled off the road turned the car off an restarted and continued about another mile. The car was struggling for power and was unable to climb a hill so I pulled over again and shut off the engine, this time I was unable to get engine or get the starter to turn over. I was close to Walmart so I bought a new battery and installed it and nothing - entire engine cluster remained dark and engine starter or solenoid would not engage or show any sign of closed power circuit. I called a tow truck and had GX delivered to my warehouse where it has sat for several months. Today I finally had time to look at it. I attached a battery charger and left it on for several hours until the green fully charge light came on.

The electrical stuff that died on the road has since come back on, I have forceful vent fan, door locks, windows, seats, mirrors, blinkers, dome light, digital clock, digital temp cluster (center console), headlight, horn, steering wheel auto position, door open beeping, etc. But still NO dash cluster in front of driver (gauges, etc) and no engine starter. When I leave my hand on the horn and turn on the lights there is no reduction in horn loudness and when I turn on the key to full start position there is no reduction in horn loudness. The battery seems to be fine and there does not seem to be an added load when the key is turned to start. I do notice that the digital clock goes dark when the key is moved to start position and clock reappears after key is returned to on position, but horn is not lowering in pitch during full key cycle. I did the horn test to see if the battery was weak when other loads were added. The ONLY thing appearing in the cluster is the red car icon with open doors and a red key icon inside of a car outline... Is it possible the computer is not noticing the key transponder code??? I have 2 keys and both keys have the same result. I do not think the computer is seeing the key.

I do notice a steady yellow light on the underside of the passenger side glove box, this yellow light would illuminate your knees to shoes if you were sitting in the car. I pulled off the plastic shroud and the yellow light wire harness goes to a computer tire pressure box and to a 4 wd computer box.

There were zero problems with the car prior to it losing all electrical and all gas power while driving before quitting, and the entire event took place from start to end in about 15 minutes.

I initially thought I fried the brain, but so many things are working I am now thinking it may be a sensor or a fuse. It almost acts like a low oil sensor is preventing closure of circuits but oil is full. The car has been very well cared for and has all services complete. Prior to this event the car has performed 100% perfect.

I am stumped. and I have never seen the yellow light on underside of passenger side glove box...

I also connected an Autel OBDII scanner and the only code I got was not a code but a connection failure - waiting for vehicle to respond - LINKING ERROR -

Help...

 

Update with a happy ending...

So I posted this thread on many lexus blogs and several people responded that I should consider checking all the fuses. One thread suggested looking at the 30 amp AN1 fuse under the big cover in the engine area. That exact fuse was dead. I researched the circuit for that fuse and it controls the ignition including the spark plug coil. I replaced the AN1 fuse and the GX started right up but died in seconds and the fuse was blown again. It also sounded like I had a leaking exhaust manifold on the passenger side. I immediately noticed the spark plug #2 from the firewall on passenger side was coated in soot. I removed the 10mm bolt and pulled on the coil assembly and the top coil box broke away from the coil shaft connected with a tail of copper wire. I pulled on the wire and the rest of the coil shaft assembly came out including the spark plug. Thats right, the spark plug was not screwed in to the head. I replaced the coil pack with a NAPA part, added a new iridium plug, added another 30 amp fuse and it started right up and remained running.

This fix ended up taking about 15 minutes and under $100, a big win win. But how in the hell did that plug get so loose. The odor I smelled was the exhaust melting the silicone boot and plastic housing. I ran codes and it came back as a spark plug coil.

How awesome is it that I know not a lot about cars and a few hours on the internet and helpful suggestions from people all over got me back on the road - THANKS to all who helped.