Any DIY to keep instrument cluster lights on at all times?

It is controlled by the CAN messages from the body control module to the cluster. I can power my cluster on the bench with only 12V+, Ground, CANH, CANL and turn the instrument cluster lights on and off. I tired to inject the cluster lights on "signal" to my truck, they came on but the next periodically transmitted BCM CAN message turned them right back off a second or two later.

Modifications to the firmware in the MCU of the cluster is the right way to fix it. I was able to "jump" two pins together on one of the chips of the board. This powered all the lights on with the key but the dimming function no longer worked. I haven't looked at or messed with it in over a year now.

The illumination wiring, posted above, running to and from the cluster is for the dimmer (built into the cluster) to control/dim all the interior button lights on the dash.

 

@Jeff_5_7 - did you try firewalling the LED message from the BCM, similar to what I did with speed? Then use the ignition message as a trigger to send the 'cluster on' message.

 

I did not but that could easily be done if you have a microcontroller inline between the cluster and the network. Two channels with pass through via microcontroller. You could generate/feed the cluster the message to keep the illumination lights on and block the BCM from turning the back off. You would also have to watch data from the BCM to turn on indicators for Fogs, Headlights, Bright lights ect. I think these signals are in the same message as the illumination one. It would take a little trial and error but can certainly be done.

I am not even sure you would need an ignition message as a trigger. Just set the MCU to broadcast the illumination on signal as soon as it powers up. All of my MCUs I use are powered on the same circuit as the cluster/key. Truck is off MCU is off, truck is on MCU is on.

Once I switched to the 2018 cluster I kind of forgot about it. The new one has the illumination come on with the key from factory.

I need to find someone with skills in reverse engineering embedded systems. I have several firmware dumps from the main MCU of the clusters. Understanding what it is doing and making changes is very difficult however and I have not made much progress. Sending current speed value to the display (instead of average speed) and keeping cluster illumination lights on with key where the first two big changes on my list.

 

I've only compiled to frozen bytecode and sent firmware through JTAG to a uC. What you're talking about is the inverse. Good luck. Send me a PM if you ever get that sorted out, I'd like to see the code.

 

Good giref, did everyone skip over my POST #22? Simple solution.


Or go down a rabbit hole and start ripping into wires and the ECU which I don't think most would do anyways.

 

I saw it. IMO it's kinda tacky and I feel like the way that glare lights up would make it worse. I like the concept of it though.

 

I have it decompiled but following thousands of lines of code and understanding where it is moving data, when it is calling functions, ect is not exactly easy.

 

+1, definitely not the tint. I bought my truck without tint and took it to a guy close to house. I do not like paying dealer markups for add ons

 

I only recommended the no tint because all of the first original posts were about how dark they were after adding tint.

 

Sometimes it's designed that way on purpose so you don't drive at night with the lights off.

If I turn parking lights on the amber DRLs are still lit and the cluster lights up. The dimmer has a little control when lights are off too but I think it's just the mini screen.

 

I stand corrected! I have more experience with the 2nd gen models.

That being said it seems like just running with headlights on all the time is the easiest way to do this. Safer too!

 

At this point you're probably correct. To Jeff_5_7 & JRS, I wish I had your brains. Pretty awesome to be able to understand the code. I'm down for some simple wiring or a possible aftermarket cluster option thats plug and play, but that's likely it. Seems as though I'll roll with the parking light option for now.

Thanks for the suggestions fellas.

 

I have a small hope a little jumper wire cna be installed on the board to force the led light driver to stay powered on with the key on/off. I need to look around at this more.

If I can ever understand the factory Toyota code in the microcontroller, a quick reflash if the cluster firmware could open up a world of possibilities and customization. One day hopefully.


I have some pretty extensive knowledge of the Tundra clusters but that’s only because I have been playing with them for over 2 years. Finally was able to pull of the 2018+ cluster swap in the older Tundras. That’s how it all started.