Author Topic: What is the blue box of this Turn Signal Circuit? Solved  (Read 1950 times)

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Offline t1dTopic starter

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What is the blue box of this Turn Signal Circuit? Solved
« on: December 27, 2018, 09:18:47 pm »
A friend wants me to build this and I have the parts. But, the schematic is not traditional and I can't tell what is going on, in the blue box. An explanation, please and thank you.



EDIT: The blue box is the relay. Solved.
« Last Edit: December 27, 2018, 09:24:41 pm by t1d »
 

Offline Rerouter

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Re: What is the blue box of this Turn Signal Circuit?
« Reply #1 on: December 27, 2018, 09:22:27 pm »
Its using an automotive relay, its using the capacitor to keep the relay closed for longer than the flash rate of the indicators,

30 is common,
87 is normally open contact
87a is normally closed contact

86 / 85 are the coil connections and dont care what polarity.
 

Offline t1dTopic starter

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Re: What is the blue box of this Turn Signal Circuit? Solved
« Reply #2 on: December 27, 2018, 09:25:56 pm »
Thank you!
 

Offline glarsson

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Re: What is the blue box of this Turn Signal Circuit? Solved
« Reply #3 on: December 27, 2018, 09:27:56 pm »
The blue box has the same pinout as a automotive relay and the numbers (30, 85,...) are the standard numbers found on automotive relays, so perhaps the blue box is a relay with a diode in parallel with the coil? :-)
 

Offline rbm

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Re: What is the blue box of this Turn Signal Circuit? Solved
« Reply #4 on: December 27, 2018, 11:53:49 pm »
The diode illustrated is in parallel with the relay coil and is a snubber circuit (reverse-polarity) to reduce spikes that could hurt the upstream flasher.
- Robert
 

Offline Brumby

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Re: What is the blue box of this Turn Signal Circuit? Solved
« Reply #5 on: December 28, 2018, 12:28:22 am »
The diode illustrated is in parallel with the relay coil and is a snubber circuit (reverse-polarity) to reduce spikes that could hurt the upstream flasher.

The diode I see is not a snubber diode since it is not in parallel with the coil - unless you want to include the complete up-stream flasher circuit as being the path to chassis.

What that diode does do is prevent the capacitor from discharging back through the flasher circuit (including the flasher globes) when it is in the off state.
 

Offline Rerouter

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Re: What is the blue box of this Turn Signal Circuit? Solved
« Reply #6 on: December 28, 2018, 01:07:00 am »
Brumby... there are 2 diodes in the diagram, so your both right.
 

Offline Brumby

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Re: What is the blue box of this Turn Signal Circuit? Solved
« Reply #7 on: December 28, 2018, 01:11:46 am »
 :palm:

I didn't see the one inside the relay.  It just looked like clutter.



Need more caffeine.
 

Offline Brumby

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Re: What is the blue box of this Turn Signal Circuit? Solved
« Reply #8 on: December 28, 2018, 01:14:18 am »
I did say this!:
The diode I see is..

 

Offline Rerouter

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Re: What is the blue box of this Turn Signal Circuit? Solved
« Reply #9 on: December 28, 2018, 01:25:31 am »
Welcome to the world of automotive wiring diagrams, trust me it gets far far worse.

Its not uncommon for them to pull stuff like this, in flat image only PDF's
 


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