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nifty relay hook up - 3 wires

Posted: Sat Feb 02, 2013 12:55 pm
by steptoe
picture here:

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Is what I found tucked way up in the dash of my Vortex - at the end of the Black Widow wiring. The thicker wires RED and WHITE are between a wire cut from the back of the ignition for 30 and 87a. The 85/86 combo is a diode feeding one, an orange wire from the alarm control box. I think it is some sort of latching relay function so once you have deactivated and got power you can restart engine if stalled without having to blip blip the remote

Anyone know of this arrangement other than once resident auto sparky Subarino ?

That diode is off 86, with the orange going to 85

Coming up..... a shot of the relay with molten solder all over it...

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copped a decent drop of solder during install, not that you can see in the shocking pic, but it started to form its own male spade terminal before it cooled - came so close to just switching it through anyway :(

Posted: Sat Feb 02, 2013 3:32 pm
by Gannon
The diode provides positive supply to the coil and the earth is switched by the immobiliser. The diode at a guess is to prevent any voltage present on the orange wire from feeding back up the red white when not cranking the starter motor

Posted: Sat Feb 02, 2013 3:33 pm
by tambox
Diodes allow a lot of neat tricks to be done.
The relay setup is a good example.

Another example is using a single wire to operate the fuel pump while cranking on LPG to help start up. Then when the car is switched to petrol the starter does not operate at the same time as the pump.

Posted: Tue Feb 12, 2013 3:02 pm
by RSR 555
steptoe wrote:Coming up..... a shot of the relay with molten solder all over it...

Image



copped a decent drop of solder during install, not that you can see in the shocking pic
Time to give back all that money you paid on photography leasons :p

Posted: Tue Feb 12, 2013 5:14 pm
by steptoe
the money the optical company pay me far outweighs the photo class fees :D