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correct way to wire to the relay?

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=92183
Printed Date: April 29, 2024 at 10:37 AM


Topic: correct way to wire to the relay?

Posted By: ewingr
Subject: correct way to wire to the relay?
Date Posted: March 27, 2007 at 11:26 AM

I have a Cruise Control arm from Rostra that is a normally closed switch. I need a normally open switch. I was told I could go through a relay to achieve my goal.

According to Rostra, the wires from the Stalk I purchased from them is like this:

Yellow = Resume/Accel
Green = Set/Coast  It is the only wire that varies between normally open and normally closed, so I presume I run this one through the relay.  It has power at all times normally, until hit button, then loses power.
Brown = On/Off - Only gets power when Cruise is on. So when turn switch on on stalk it gets power.
Red = Brake Switch -  Constant 12
 
So, with that, I am thinking I would do this:
 
Stalk Yellow Wire--> Resume/Accel from my PCM
Stalk Green Wire--> Relay, Based on this diagram.  Would I wire this as the Green wire, and if so, which of 2 basic diagrams?
PCM Set/Coast wire--> to the Blue wire on the same diagram.
Stalk Red Wire-> to PCM Brake wire.
 
Is this right?


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Thanks
Roger



Replies:

Posted By: ewingr
Date Posted: March 28, 2007 at 10:01 AM
Does noone have a clue, or does my question not make sense/

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Thanks
Roger




Posted By: ewingr
Date Posted: March 29, 2007 at 7:51 PM

Well, I have communicated with someone that tells me I do NOT want to change polarity. I"m told that the difference would be that on teh one wire, when it is normally on, I need it to be off, and vice versa.

I looked through the relay diagrams, and with my lack of understanding about relays, I don't see diagrams there that stands out as how to do that.

Still no help here?



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Thanks
Roger




Posted By: hotwaterwizard
Date Posted: March 30, 2007 at 3:21 PM

A relay can do the job.

On an automotive relay there are 5 pins. Each is marked with a number.

30 is a switching common for the relay output

it is normally closed with 87a and normally open with 87

85 and 86 are the coil.  The coil controls the switching action without being in contact with all of the other pins.

if you hook your switch to the coil of the relay it will switch the contacts from closed to open

Here is how you do it.

Take the wires that go to the switch hook them to a relay pins 30 and 87a.

Now the switch has no wires. Add a hot wire to one side of the switch and pin 85 of the relay to the other.

Ground pin 86 of the relay to the chassis of the car.

When you switch the switch it will do what you asked for.



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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !





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