wigwags on a canbus car

Hi guys... I am looking at doing a little project on my '06 Astra...... I want to do something along the lines of a Safety Car Lighting with the alternating Headlights, Breaklights and indicators.... I also want to put something in grill... Before I go asking for wiring diagrams etc. I need to find out if it will work with a Canbus system. Does anyone know if it will? There is an option for the Special Cars (i.e. emergency vehicles) in Tech 2 but I dont know what this is for and therefore dont wanna be playing about with it.. If anyone knows if it will work I will be eternally greatfull. Chris

Seriously....130 views and no reply!!!!! lol someone must know the answer

The can bus doesn't control the lights, it only covers the control side of things. The BCM (or some other module) will receive the CAN signal and will switch the lights on as necessary. Controlling the lights, after this module, should have no effect on the CAN system. The only thing to keep in mind here is that you won't be able to tap in to any of the wires at the switches, you'll have to do it at the lights.Kevin Pierson

ahhhh Ok cheers for that.. I only asked as I know that HID kits bring up issues due to the low level of voltage and a quick change to the settings via tech 2 to enable the afl option sorts this....via the can system... But if i can tap into the lights and run it off a combo of switches and modules etc... my next question is..... Anyone be able to supply a wiring diagram along with what i will need etc... I want to do headlights and front fog lights, rear fog lights and reverse if possible alternating....ie right headlight left front foglight together and left headlight front right fog light many thanks.... i have tried looking on here but think i am being blind

Headlights will have white and yellow primaries, side lights will have grey primaries you can test for the others, good luck around the front fuse box, it's a real PITA. Personally I wouldn't touch this with a bargepole!

chrish sri wrote: Hi guys... I am looking at doing a little project on my '06 Astra...... I want to do something along the lines of a Safety Car Lighting with the alternating Headlights, Breaklights and indicators.... I also want to put something in grill... Before I go asking for wiring diagrams etc. I need to find out if it will work with a Canbus system. Does anyone know if it will? There is an option for the Special Cars (i.e. emergency vehicles) in Tech 2 but I dont know what this is for and therefore dont wanna be playing about with it.. If anyone knows if it will work I will be eternally greatfull. Chris

Hi!

I've done this on my car which has CANBUS and PWM for powering lights etc.  It's VERY easy to do if you are OK with a soldering iron, diodes, relays and LED flasher units.  I will try and explain.  If you are no good with car electrics or the basics, please don't break your car!

At the moment my car has two alternating (wigwag) rear foglights.  It's possible to do any combination of lights up to about 20A, or more if you get a much bigger relay.  A basic wig-wag can be made from just two components, a normal flasher unit designed to work with LEDs and a relay.  The flasher unit is the electronic type and some are better than others.  You might need to look at the flash rate.  The idea is to use the flasher unit to switch the relay coil on and off.  With 12v to the common terminal of the relay, you can take one wire to one light from the normally open and one to the other light from the normally closed.  So as you put 12v to the flasher, you also need to link that 12v to the common on the relay.  Once powered up, that 12v will go from one contact to the other depending how fast the flasher is.

On a car using CANBUS you should always take the precaution of using diodes as on GM/Vauxhall cars they use a PWM (Pulse Width Modulation) unit to supply all the lights - I have no idea if the output of it is protected, so best to be on the safe side.  For foglights a 6A diode will do.  You need 4 diodes to do 2 lights as a starting point.  Say it's your front foglights you want to flash from left to right...

Start by getting 2 of the diodes and position them together so that both white bands are next to each other.  Twist together and solder only the two wires and the striped end.  Do the other two diodes in the same way.

Find the wire to each foglight, it must be the positive wire.  Cut it and take one set of diodes and solder the twisted wires on to the wire going to the actual light fitting.  So the white stripes are nearest the lights.  Connect the wire that went  from the car to the light to one of the diode wires on the opposite end.  The spare wire from the diodes will go to your flasher circuit (relay contacts).  Do the same on the other side.  Insulate everything and possibly use self amalgamating tape if any water or spray will get near it. 

If you think about the circuit, 12v from the car will pass through one diode to the light, but will be blocked from going back up to your relay/flasher.  You will get a 0.4v voltage drop when the lights operate - but you will not notice it.  If your lights are off and you operate the flasher, the other diode will allow the voltage to pass, and that will be blocked from going back up to the car and damaging the PWM unit.  Diodes will only pass a voltage in one direction.

If you have the flasher operating and decide to switch the lights on at the same time - they will stay on together as 12v is going to the lights from two sources, but they are isolated from each other.

I hope all that makes it a bit clearer for you. 

If you decide to flash say two full beam lights (NOT HIDs as they don't like it, the ballast units blow) and two foglights you can do that too.  Use the two diodes in series with the supply to each bulb.  This time take one wire from the flasher to the spare end of one diode and also connect it over to the other one.  Then take the second wire from the flasher to the foglights using diodes in the same way. 

I'm no good with art packages so a diagram would be a challenge!  It should give you the basic idea of how to do it.

I've never seen the option with TECH2 on a GM/Vauxhall for use on emergency vehicles.  Most use the method I described with diodes and relays, but the control modules are more elaborate and much more expensive.  Everything goes in the boot and involves a major alteration to the car wiring.  It's possible on some cars the factory will have a wiring loom designed to allow people to tap in to various cables to lights etc.  In some GM/Vauxhall cars there is a second fuse box in the boot.  It's behind the panel on the left hand side as you look inside.  That's called a "REC" Rear Electrical Centre.

Some have it, some dont,  but if you do it is possible to take a 12v supply from the two big red wires feeding it.  Your project will certainly take a bit of wiring and putting cables under the trim and also poking some through to under the bonnet from behind the glovebox.  You could put the switches on the flap under the handbrake, by the TECH2 socket.

Good luck with it all.

V105 You are extremely patient, good for you! I wouldn't have thought of the diodes but then knowing about needing a diode block on the ACC for Opel/Vaux when adding an aftermarket h/unit or car kit helps. I've done a couple of hard wire (not CAN) alarms on them, a nightmare. The biggest problem you will find is making them understand and listen to you.