Altering Vehicle Exterior Lights (Indicators)


Looking at feasibility of changing the default actions of a vehicle’s rear lights

Essentially we need to stop the indicators from flashing with the brake lights and have the corresponding reverse light to flash instead

Has anybody tried this? Possible?



need more info make, model and year of vehicle?

A variety to be honest! Newer Ford Mustangs / Chevrolet Camaros are common

As a background we ship vehicles into the UK, mainly from the USA. The lights have to be converted to UK spec, mainly this involves separating the brake feed from indicators and then changing to amber flashing bulbs, either using LED to flash through red clusters or using the clear lens that usually hold reverse lights and then using dual colour LED to function as indicator and reverse

If we can get the car to stop performing the default action for brake / indicator using + spoofing CANBUS signals, perhaps we can do this easier and with less wiring than current method involving relays and feeds from brake switch etc

I hope it is possible!



I can help with the GM side here is what I have accomplished

That is awesome, our solution needs to work to stop the default action while the car is running. As a test if we can get a corresponding reverse light to flash instead of the expected indicator I think it could work and will reduce a lot of wiring we currently have to carry out

this is example code for GM chevy volt 2012 this only controls for 3 seconds unless you constantly send the tester message every 3 seconds to keep it in that mode.
this is code to turn off all lights
241 07 AE 00 00 00 00 00 00 all lights off
241 07 AE 02 00 00 08 00 00 turns off reverse lights
241 07 AE 02 00 00 08 08 00 turns on reverse lights
play with the data bits and it activates different lights it also controls interior lights too.
hopefully this can jump start what you need.

Excellent, thank you - do you think possible to detect a certain signal, e.g. right indicator - block it / modify it, and instead cause the right reverse light to flash?

you can detect via CAN message whats going on with the lights but I haven’t dug that deep. I know every light in GM cars are controlled by the BCM.

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Your biggest issue is going to be with the BCM… The programming of the BCM generally contols the output of the lighting. The BCM has triggers that go right to the relays so to do what you want you really need to change the BCM program.

Things like the turn stalk and possibly brake signal are directly wired to the BCM and the BCM does everything so you really end up having to do everything with the BCM programming. Otherwise you have to rewire. Some other vehicles may have a special control unit for the rear lighting but I don’t know that any GM’s that I have looked at do.