Avmanager

I have an issue with the Instrument Panel lights on my 2007 SC430 so I thought I would hit up the experts here The issue I am having is that the instrument Panel lights cut off when the lights are in auto or headlights are turned on and it gets Dark. I know, the next response from everyone is going to be " Did you turn the dimmer ****" The answer is yes.... I even purchased another one off Ebay hoping that it was the $15 dimmer ****, but it wasn't. I put the new one/ used one in and the car behaved exactly the same. I also took my original switch and put it in my aunts 2006 SC430 and it worked fine. I took hers that worked fine in her car and swapped into mine and the behavior stayed with the Car. I was hoping I had just purchased a bad switch. So not really sure where to go with this one. All the other lights dim and do as they should when it gets Dark outside or the headlights are turned on. I can turn the Dimmer **** to the full on all the time position and it turns the dash lights on. I have unhooked the battery, I have reset most of the fuses to make sure that was not the issue. I have not reset the relays. Was hoping to get some guidance on the next steps.

Bgw70

Avmanager

Yep,
Instrument Cluster = Tachometer and speedometer. It has me baffled since I can turn it all the way on at the switch and it will work when turned all the way. It just does not function correctly when going into night mode. I looked at the wiring at the plug in and didn't see anything loose on that end when I changed the switches out.

Bgw70

Avmanager

Yes,
So when I turn the Headlights on, the cluster lights go off if the dimmer switch is not turned to the all the way on position. This wouldn't bother me, but what it does is keeps the navigation screen on full bright even when the Dash light sensor in the upper right hand cover senses its dark. So the Dimmer switch only comes into play if it is in a dim situation in auto, or if the Headlights are switched on the selection below auto.

I keep wondering if I still have a bad ECU or something somewhere triggering this situation, along with the weird fuel door/ trunk popping issue that has just surfaced again as well. I ordered the Tech stream cable/software today that I will hopefully get configured by end of the week to see if that will tell me anything on the car. The Fuel door & trunk popping open have also happened as I am driving it as well. So those are my only Gremlins I have been chasing on this car. The instrument lights, trunk and Fuel door popping open.

Coleroad

Avmanager

I'm not sure, I had looked and done searches on the SC430 Forum as well as all the club lexus forums to try to find something close to this to do some troubleshooting

Coleroad

Avmanager

But with essentially trying 3 different switches and all 3 behaved the same in that car, then trying those switches in another SCS430 and it worked perfect, I think I can rule out the Switch/Dial

Coleroad

Bgw70

Retroplay

I will look more closely when I get out of work. I just want to clarify, all other light dim correctly under control of the dark sensor, but the instrument cluster just shuts down?

And yes, I would like to hear more about the fuel door issue.

Thanks

Avmanager

Yes, all other lights dim correctly under the Sensor and the Instrument Lights just switch off. I can turn the switch to full on, and they all light up

The Fuel Lid and the Trunk Pop Open on their own. I can leave the car unlocked In the garage for a few hours and come back and both are popped open. If I lock the car it does not happen. About 2 weeks back, both the Fuel door and the Trunk were both popping open if I pressed either the trunk release or the fuel door release. I pulled the fuse in the ECU JB in the trunk and it fixed that type of behavior, but I am still having them pop open randomly. It also does it while I am driving it. Ive tried taking all the fuses out from all the junction boxes and reseated them. I disconnected the battery and reconnected it as well. When I removed the Carpet in the trunk, I could see that the trunk had gotten wet at some point as a few of the bolts on the Nav brackets had slight rust on them. I did not remove the ECU out of the car and take it apart or anything. But was thinking about taking the fuse box apart so I could look at the under side on it. That's all the weird issues with this car. Car had about 4K miles on it over a 6 year period, but both Trunk lights were disconnected when I bought it. I am suspecting the fuel lid and trunk lid popping open has been happening a while and the trunk lights were draining the battery. This one has me stumped......

Retroplay

My initial suspicion is a multiplexer issue. I need to check if the trunk ecu and the instrument cluster are all on the same BEAN bus.

Still stuck at work, but I will check my diagrams when I get home.

Do you have the techstream cable now?

Avmanager

I do not have the Techstream cable yet. Its showing delivery from Amazon tomorrow, then I will need to get it installed. Im thinking about not trying to install it and just emailing and having them go ahead and setup a Teamviewer session to install. I was figuring I would save myself some time and trouble that way......