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Help with car wiring

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DJAZS

New Member
Hi, this may be a very simple question, but I don't know how to sort out this problem, hence why I am asking here for help!

I am upgrading dashboard/switches in my car to a newer version, but I have come across a problem with the hazard switch.

Basically, the original switch from my car was latching, so when it was pressed, it would make a circuit and provide a continuous ground feed to the necessary input on the car's electronics module, and the hazard lights would flash. When the switch was released it simply broke the circuit again.

Now, on the facelifted car dashboard, the new hazard switch is non-latching, when it is pressed it provides a momentary ground pulse to the electronics module and turns the hazards on. When it is pressed again it provides the same pulse to turn the function off on the electronics module.

So..... I need to make my new non latching switch to provide a permanent earth to the electronics module on it's first press, and to remove the earth when pressed again! If anyone can offer any guidance as to a circuit I could use to produce this effect then I would be most appreciative!

Thanks for reading my ramble if you've got this far! :)
 

user_88

Member
Problem definition ...
You want to control the electronic board to ground connection .... utilizing a latched switch .... where a momentary input changes the switch state...
Is this on the right track?
 
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DJAZS

New Member
Nearly!

I want to control the electronic board to ground connection .... utilizing a non-latched switch .... where the electronic board to ground connection needs a permanent connection, until the non-latched switch is pressed again!

I'm not sure these will be of any use, but this is the earlier setup:

8788-earliercarssetup.png


And this is the later setup:

8789-latercarssetup.png


So basically, I have the early electronic setup, but want to control it with the switch from the later setup!
 

Mike_2545

Super Moderator
Try this, it takes a momentary switch input and latches the relay till it is pushed again.
 

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user_88

Member
Do you have access to a wire or pin that comes from the mechanical side of the switch ... and conveys a switching signal? This isn't completely clear from the diagram.

You have to have some sort of switching signal to activate a toggle flip flop, a relay, or whatever.

Check the voltage on the pins of the non-latching switch, in order to see if any of them are active or change states, as you simultaneously press the hazard switch.
 

DJAZS

New Member
The switch only has 3 pins, a common ground, a feed for the switch illumination, and the switch output, which is connected to nothing normally, and momentarily connects to ground when the switch is pressed. So on the later setup there is no signal from the switch other than a momentary ground pulse to switch the hazards on, and an identical pulse to switch them off again. On the earlier setup, as the switch is latching it supplies a permanent ground when pressed, and removes it when pressed again, so I need the momentary pulse type switch to trigger 'something' which will provide a permanent ground output once triggered, and when it recieves a second ground pulse, remove the permanent ground
 

user_88

Member
What is the voltage on pin 6 of the non-latching new switch? This is without pushing the hazard switch button. Is it about 12 Volts? This would be the pin that you referred to as the switch output ....probably.
 

user_88

Member
It would seem that there must be a wire from the hazard switch .... going someplace ... maybe to the module labeled A112. This wire would provide a switching signal for the latch circuit which you require for the new switch.

If you have the wiring diagram, maybe you could trace a wire from the hazard switch to the A112 module, or someplace in that vicinity.
 
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