100 series Dashlight and Taillight out

[OHUZJ100]

Not sure where to start on fixing this weird electrical issue. One night I start the vehicle and the dash and tail lights are no longer illuminated.

Replaced 15a fuse that was blown started car, same thing. I had the Toyota shop where I got an alignment check while they still had it but to no avail.

I have an aftermarket radio, and Reese tow package. This year also has the dimmer dial (1998). I have seen this issue on 80 series, and other non tlc models. Search on mud does not pull up conditions like mine.

If you have ideas let me know

 

[OHUZJ100]

Also brake lights, indicator lights, and head lights work.

 

[Inukshuk]

A tail light bulb may be out. The smart Toyota engineers design it that way to alert you to the blown bulb.

 

[On the RX]

I have a test light of you need to borrow it.

 

[OHUZJ100]

A tail light bulb may be out. The smart Toyota engineers design it that way to alert you to the blown bulb.

That's amazing 🤣 I was looking up answers freaking out. I was reading about a relay either for the (dimmer?) or (tow harness plug?).

Either way, I had the lights on auto last night and everything is working. I guess maybe the shop where I am getting alignments is replacing them for free! Fine by me. You must be right sir, but ill never know until next time. Thanks for the 101 @Inukshuk

 

[OHUZJ100]

Update: I checked every single bulb they all light up and work. None of the filaments are broken either.

So, I have no Dashboard lights, AC control light, or Taillights. All of the lights I'm speaking about are tested and work, but go out and blow a 15a taillight fuse.

I am thinking relays?

 

[J1000]

take all of the bulbs out on that circuit and put them in one by one and see which one causes the fuse to blow

 

[Inukshuk]

soon I have to troubleshoot a GX470 with no interior dome lights

 

[Stuckinthe80s]

Did you ever resolve this? Also, does your odometer work? I had a no dash lights issue and the odometer went blank just to find that the dimmer switch connector had come loose. For some reason the power to the dash and odometer routes through that switch. My Hundy is a 99 so I think the wiring should be the same as yours.

Something else I found out is that the computer gets it’s speed input from the speedometer. As well. I had a speed sensor code pop up when the dash went out because it is an electronic speedometer.