How Do I Do This?

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=6987
Printed Date: June 24, 2025 at 5:02 PM

Topic: How Do I Do This?

Posted By: 7PSI_CRX
Subject: How Do I Do This?
Date Posted: December 22, 2002 at 6:44 AM

Hello, nice informative site here.

My Question:

I have a switch.

One side is attached to the chassis ground.

The other side to a 1 Watt 12V Lamp.

Now here's what I want this switch to do: (Besides activating the original lamp)

I need this switch, (When grounded) to turn another simple circuit (POS or NEG) OFF!

Anyone want to take the time to help me out here?

The simplest way the better. (Least amount of relays, etc)

I know it sounds simple, but I'm stuck.

Thanks.

Replies:

Posted By: brianh
Date Posted: December 22, 2002 at 3:17 PM

All you need to do is to tap the ground wire on the bulb side of the switch(not the side that goes straight to ground) . Run that wire to pin 85 on the relay. Then get a wire that is constant 12 volts and put it on pin 86. Then take the positive wire of the circuit you want to turn off(cut it) and put one end on pin 87a and the other on pin 30. So when the light sees a ground(to turn on) this picks the coil of the relay up. You wired the circuit you were going to turn off through the normally closed contact so when the relay turns on the contact opens turning the chosen circuit off. If you need more help feel free to e mail me directly. Good luck and let us know how it turns out. Brian

Posted By: 7PSI_CRX
Date Posted: December 23, 2002 at 5:17 AM

Thanks Brian.

Believe it or not I figured it out myself about 15mins after posting.

(Use the NC terminal of a relay)

Thank you again, it'll turn out fine I'm sure!

John

Posted By: brianh
Date Posted: December 23, 2002 at 6:06 AM

Im glad. Good luck. Brian

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