RG Auto Headlights

#1
someone asked about auto headlights on another forum and i am messing around with arduino to create a auto headlight module for the Colorado without it and I thought I will post the info here too.
I will just repost my last 2 posts...



I worked out the right light settings it worked well doing a debug test printing the data and switch state to the lcd screen, got it to match the vf commodores auto headlights almost perfectly.

so I have built the module.


its cost $40 in parts at jaycar to build it and might be another $5 or $10 for a plastic case at jaycar to put it in but I have a few of those.

once I install it into my Colorado and test it with the headlight switch connected I will post the schematics and scripts needed to build the module and program it.
 
#2
I should have expected this in a new vehicle, the Colorados headlight switch is actually a canbus module.
it turns the lights on and off using canbus messages so its not your old traditional type of switch and I guess that's why there are no auto headlight kits floating around because you would need to interface with the ecu/bcm via the canbus and send the right data packets telling the headlights to turn on.

but lucky enough the switch holds its state and sends the packets down the canbus when you disconnect the swcan wire and reconnect it.
so this auto headlight module still works by disconnecting the swcan wire and reconnecting it.

the good thing is its only 1 green wire on the back of the headlight switch that needs to be cut to toggle the lights on and off


here is a video of a test of it in the vehicle using a floodlight to simulate daylight to the light sensor.

now I need to go driving to test it properly.

something else that might be needed is a way to override the module to force the headlights switch on if needed.
maybe a simple switch to connect the swcan wire overriding the relay in the module so the vehicles headlight switch operates like normal.
 

Spooner

Well-Known Member
#4
Very nice mate , well done . The things some people can do constantly amazes me.
Im an electronics dum dum 101 , lol . I used to play with valve wireless radios and tv's when I was a kid.
How times have changed :)
 

Chatty

Well-Known Member
#6
something else that might be needed is a way to override the module to force the headlights switch on if needed.
maybe a simple switch to connect the swcan wire overriding the relay in the module so the vehicles headlight switch operates like normal.
What about a pass-through (T) connector on the back of the headlight bulbs? One leg connects to the bulb. Canbus stays connected to one leg of the T and operates as it is now - enabling you to turn the headlights on as normal. Feed the Arduino module from an ignition feed and connect it to the other leg of the pass-through connector so it acts as an auto headlight switch. Having +12V applied to the 12V feed from the Canbus to the bulb shouldn't be an issue.

As for me, I have auto headlights - if it's getting dark and I haven't switched them on SWMBO always reminds me...
 
#8
What about a pass-through (T) connector on the back of the headlight bulbs? One leg connects to the bulb. Canbus stays connected to one leg of the T and operates as it is now - enabling you to turn the headlights on as normal. Feed the Arduino module from an ignition feed and connect it to the other leg of the pass-through connector so it acts as an auto headlight switch. Having +12V applied to the 12V feed from the Canbus to the bulb shouldn't be an issue.
that is a pretty good idea but the problem with newer vehicles now is the vehicle will detect when a headlight bulb is blown by measuring the load that is created by the bulb, when the bulb blows that load is nothing so the canbus will display an error to the instrument cluster about a blown bulb.
so if you were to have the headlight switch on and disconnect the wire to the bulb it would have the same effect as a blown bulb.
I guess this could be solved by making something that would put a load onto the wire when the bulb is disconnected, they do this in newer hid kits that are labeled "canbus compatible"
 
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#10
I was thinking about the Trailblazer 2017 model and it has the exact same cut out for the headlight control panel fitting as the MY16 colorado 7 trailblazer. I wonder if in the 2017 you'll just find 2 wires hooked up to light sensor and all the light smarts are just in the headlight control panel. If anyone in here could post a photo of the wiring from the 2017 model that would help a lot
 
#11
normally with most holdens the wiring harness is the same in the lower and upper spec models they just change the modules plugged into the harness.
the light sensing circuit should be in the headlight switch that has the off/AUTO/parker/on function and the lightsensor will just clip into the dash where the blank plate is and there should be a plug for the sensor under it somewhere.

you can buy the OEM light sensor on ebay for from your local dealer using the part number.
http://www.ebay.com/itm/Ambient-Light-Sensor-ACDelco-GM-Original-Equipment-13578461-/162424229300

the headlight switch with the "off/AUTO/parker/on" modes I would probably look for at a local wreckers.

but that's all based on the theory that the headlight switch controls the sensing mode and you have the wiring for it all.
I couldn't tell you without having the switch and looking at a 2017 Colorado, but that being said the 2015 Colorado and the 2017 Colorado with the trailblazer decals are pretty much identical apart from a minor interior facelift and the headlights/grill. the important stuff is all the same.

on the harness to my light switch is about 5 or 6 wires.
1 = CAN wire is to control the headlight/fog/etc functions and 2 of them would be for + and - for the illumination led so that leaves 2 or 3 for ?? light sensor maybe?
 
#12
I managed to find a headlight switch from a 2017 trailblazer with the auto headlights.. the physical port is reversed but the pinouts were exactly the same so it was plug and play. seems to work just fine (except the auto part doesn't work yet) . now to hunt down an ambient light sensor and figure out if it uses that unused wire or not.
 
#13
I managed to find a headlight switch from a 2017 trailblazer with the auto headlights.. the physical port is reversed but the pinouts were exactly the same so it was plug and play. seems to work just fine (except the auto part doesn't work yet) . now to hunt down an ambient light sensor and figure out if it uses that unused wire or not.
Talk to someone at holden parts and ask for the part number for the ambient light sensor for the 2017 model your switch came from.
You might find it on ebay or need to order it through holden parts
 
#14
After some Facebooking and a nice gentlemen on the colorado groups finding me some tech docs about it. it looks like the 5th wire (not wired in our RG's) is 'Headlamp Switch Headlamps Off Signal Control' and looks to be the wire I'm looking for. however according to the tech docs for a My19 model, it doesn't go directly to the sunload sensor it goes in the BCM module according to the diagram. so we may be at a dead end.

1. Lighting Control Switch Reference
2. Not occupied
3. Headlamp Switch Park Lamp Signal
4 Headlamp Switch on Signal
5. Headlamp Switch Headlamps Off Signal Control <--- the missing wire
6. Ground
7. LED backlight Dimming control
8. Not Occupied
9. Run/Crank Ignition 1 Voltage
10. Headlamp Leveling Control
11. Not Occupied
12. Lighting Control Switch Signal.
 
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