Dear CL members,

The back-light of my climate control doesn't light up. All the controls are still functional though. Also the back-light for door panels are out too. My friend told me to check for blown fuse, but I couldn't find any blown fuse. I hope I didn't short any wire. I have a dashcam that fuse tapped into IGN-1. sometimes the dash cam doesn't power on until i unplug and plug back in.
Please help! Much appreciate it!

 

Did you try unplugging the dashcam and see if the problem is resolved?

 

yes, I stopped using my dashcam for a week now. It didn't fix the problem.

 

So sorry. Someone with more knowledge will post soon. Best of luck!

 

All the interior illumination lights are powered by one fuse...the 7.5A Panel fuse.
So if that fuse blows, all interior illumination will be gone...if the illumination of a particular component is out, then it's either the component of the wire harness.

To confirm, was the dash cam plugged into IGN-1 fuse or ECU IG1 NO.1 fuse?

Have a look around at the other interior illumination and confirm that everything else is actually working.
Also, check your dimmer switch and see what happens if you max out the brightness...does anything change?

 

It's actually 10A fuse IG I NO.1. I believe this fuse is for the gear shifter because when I unplug the fuse, I cannot change the gear lol. I checked all the buttons and everything is functional even though they don't light up. When I maxed out the instrumental panel brightness, the lights that are dead are flickering and some are just completely dead. I uploaded a video file but it's hard to see in the video that they are flickering. As I lower the brightness, everything is dimmed. Is there suppose to be back light for the windows lock on driver door panel? What should I do?

 

The first thing to note is that all the interior illumination lights are LED's. This does not include the Map lights or the door courtesy lights (the ones at the bottom of the front doors).
The illumination lights are the ones found back-lighting buttons and displays.
And yes, the Window Lock switch does have an LED back-light that should be on.
I've attached a wiring diagram so you can see all the LED's that are supposed to light up. Got to page 3 and find the 7.5A Panel fuse (in the gray box). At the bottom of the fuse you will see two "G" (green) wires that leave the gray box, they supply power to all the LED's in the components attached to the "G" wires (page 3 to page 10)...including the A/C Controls and Window Lock switch. The LED's in the diagram can be identified as black upside down triangles with two black arrows on the right, pointing to the right and upwards. You will see that there are a ton of LED's inside the car.
Figure out what's not working and let us know. Usually when you see LED's flickering it's due to a voltage supply issue...meaning that the 7.5A Panel fuse may not be blown, but if it's loose in the spot it's installed, it may not be making the best contact.
There are fingers inside the slot that grab the blades of the fuse when it's inserted, if those fingers are not tight to the blades, it can cause a poor contact...or if the blades are dirty, that could also cause poor contact...and therefore the proper amount of voltage is not reaching the LED bulbs.

 

Thank you so much for your help Sasnuke, I do not have the skills to check the wires. Should I bring my car to dealer or a local mechanic? My car ran out of warranty already because it's at 54k mileage. what is the estimate price to fix this issue?
I think I used too much pressure while inserting the fuse when I was checking for blown fuse. That might be the cause of the problem. If that's the case, Do I need a new fuse box?

 

No need to really check the wires at this stage, the diagrams I attached was more for you to identify what bulbs should be working, versus what bulbs are not working.
Realistically you won't know if a component has a bulb that is not working, since it's not working...like the Window Lock switch.
If you can tell us which ones are not working...or...if the list is shorter as to the ones that are working, we might be able to suggest some basic next steps you can do.
For instance, if you say a specific group of items is not working, it may be that they share a common power wire, or a common ground wire...maybe it just a loose ground bolt that needs tightening. Really anything is possible at this point. Like, where is the camera grounded?
We know that the AC controls and Window Lock switch don't light up...what else is not lighting up??

Good news is you can't push the fuses in too hard...the way the fuse box is designed is that the plastic body of the fuse will bottom out in the slot while the metal blades intersect the fingers inside the slot.
So the fuse will stop at the same place regardless of how hard you press it in.

 

Sorry for the late reply, I tried to follow the G wire on page 3 but I got lost in page 5 lol I have no clue how to read this. But I can tell you what bulb is not working visually on my car.
Auto Climate - Completely Dead
Increase Fan Speed - Very Dimmed Flicker
Climate mode - Very Dimmed Flicker
Side mirrors defrosting - Very Dimmed Flicker
Closed Ventilation - Very Dimmed Flicker
Open Ventilation - Very Dimmed Flicker
Dual - Completely Dead
Driver & Passenger Seat Heater - Dimmed to dead
Passenger Seat Cooler - Completely Dead
Windows Lock - Completely Dead

I hope that's useful information for you to help me. I really hope I don't have to pull the entire center console out to replace the bulbs.
Such a disappointment car, I might of got a Lemon. I already been to the dealer 3 times to replace the Side mirrors due to Blind Spot Monitor System failure. I did not expect this interior illumination issue based on the fact that my car is still pretty new. Older generation Lexus rarely have this kind of issue. Electrical problem is the worst.

 

From the sound of it, and I think Sasnuke would agree, likely not your bulbs.
Power Issue originates in the system before your bulbs. What I hope is it's not a wire issue somewhere between fuse box and bulbs.

Sid you try inspecting the fuse location? Making sure its snugly fit? Might as well try and new fuse while your at it (although likely useless) but check the connections on the fuse plug itself.

 

Let me ponder this while I look and the wiring diagram and get back to you.

The wire diagrams are fairly complex these days, so don't worry if you got lost going through it...sometimes I have to backtrack myself cause there's 5 wires all the same color running beside either other page after page.
It does help if you print it out in color and tape them together going left to right...meaning page 2 is taped to the right of page 1, page 3 is taped to the right of page 2, and so on...
I'll have a look and hopefully have a meaningful suggestion tomorrow...the list you provided will help narrow it down (in my head I'm saying 'Oh god I hope so' lol)

 

I already try swapping another 7.5 Fuse with the 7.5 Panel Fuse. It wasn't helping. Of course when I pull it out, nothing lights up.
I used my multi-meter to read the voltage. Here is the voltage for the 7.5 Panel Fuse.

 

Have you check the dimmer control on the left of the steering wheel? Try to toggle the Up and Down button to see if that change the brightness. May not be the case but worth a shot.
That voltage reading doesn't look right. Make sure the parking light is on and try to read the voltage again. If the fuse is out, it should read at least 12+V on 1 leg of the fuse. If the fuse is on and it not blown, the voltage should read 12+V on either leg. If the voltage is not at that level, you have a bigger problem. Time to trace the wires.

 

I already adjusted the dimmer to the max, it did changed the brightness but not everything.
My headlight was on when I tested the voltage. Oh god, wiring problem is a nightmare.