Relay question

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=10173
Printed Date: July 19, 2025 at 2:26 AM

Topic: Relay question

Posted By: TripleX5®
Subject: Relay question
Date Posted: February 27, 2003 at 6:21 PM

I have a bmw X5 and want to wire up my radar. So heres my situation.

I have a rack unit with a bunch of buttons on it. Heated seats, truck open, etc located on the dash. One of the buttons is marked RDC ( for tire pressure ) which is not being used. Its basicly a plunger switch. You push the button and it completes the curcuit, release the button and it breaks the curcuit. What relay should I use in order to send power to a radar via this plunger switch? If its even possible.

In other words I want to be able to turn on the radar with this switch without having to hold the button down.

Thanks

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Replies:

Posted By: TripleX5®
Date Posted: February 27, 2003 at 6:52 PM

Just for the record. Its a normaly open momentary switch.

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Posted By: wiremadness
Date Posted: February 27, 2003 at 7:48 PM

I am assuming you mean a radar detector when you say "radar." If you are refering to a radar sensor, the same basic information applies. What you need is what is called a "latching relay." What this does is turn a momentary pulse into a constant output when you push your factory switch. When you push it again, it turns it off.

Depending on the type of latching relay you get, you might need to add an additional relay to invert the pulse ( positive or negative) or to handle the current draw.

Hope this helps!

Chris

Posted By: TripleX5®
Date Posted: February 27, 2003 at 8:11 PM

Hey Chris

I'm sorry, yes this is for a radar detector. V1 to be exact.

Where can I get this latching relay and how does the radar get wired up.

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Posted By: Sonic2002GT
Date Posted: February 27, 2003 at 8:12 PM

Where can I get these relays? I'm very new to relays, and there are several things I'd like to do similar to TripleX5

Posted By: TripleX5®
Date Posted: February 27, 2003 at 8:15 PM

TripleX5® wrote:

Hey Chris
I'm sorry, yes this is for a radar detector. V1 to be exact.
Where can I get this latching relay and how does the latching relay get wired up.

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Posted By: Sonic2002GT
Date Posted: February 27, 2003 at 8:19 PM

Sorry... I had already started writing that before you had posted...

TripleX5® wrote:

TripleX5® wrote:

Hey Chris
I'm sorry, yes this is for a radar detector. V1 to be exact.
Where can I get this latching relay and how does the latching relay get wired up.