Relay on Dome light supervision
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=61937
Printed Date: May 16, 2024 at 5:39 AM
Topic: Relay on Dome light supervision
Posted By: mybimota
Subject: Relay on Dome light supervision
Date Posted: August 23, 2005 at 11:20 PM
Why would some one use a relay on Dome supervision?
thanks
Replies:
Posted By: endless talent
Date Posted: August 23, 2005 at 11:55 PM
Depending on the vehicle, the domelight may be able to be triggered by a few different methods: 1) Grounding the door trigger on a (-) trigger system 2) Providing the door trigger 12V+ to a (+) trigger system 3) Grounding or providing 12V+ (whichever it is looking for) to a "Domelight" wire, which is just a factory trigger wire that goes to or from the BCM in order to turn the domelight on. In any case, it is advisable to use a relay to convert the typical 200mA (-) output from the alarm's domelight output into the correct state for your particular application. If you have ever seen a domelight supervision output connected the lazy way, where you send the output from the alarm to a (-) door trigger output in say, a Honda, you will notice that the domelight does not light up all the way, since the (-) from the alarm is not sufficient to trigger it correctly, not to mention there is a possibility of frying the alarm module by connecting it's feeble ground output to a circuit that is looking for a higher current (-). The relay is basically using the 200mA as a (-) pole input at "85" where 12V+ is at "86" and sending the appropriate output (12V+ or GROUND) to your domelight trigger input or a door trigger in cases where it is recommended instead, as with most imports. Many Ford's, however have an actual "domelight" wire that when triggered with 12V+ they light up the interior lights as well as running board lights or others, such as the case on their SUV's. Hope that helps explain things! -------------
Posted By: mybimota
Date Posted: August 24, 2005 at 8:59 AM
The reason why I asked is that my Mazada 3 has a relay on the dome. Every time I open & close my doors there is a buzzing of the relay. I took every thing part to see what was the buzzing/rattling and it was a relay.
When I bought the car it had a compustar 900 remote/alarm on it.
what is wrong?
What should I do?? I have no experince on the compustar line just DEI and Astroflex.
thanks
Posted By: dualsport
Date Posted: September 27, 2005 at 9:33 PM
Is the relay part of the alarm installation? Only reason I can see for a relay buzzing is if the relay coil was wired in series with the normally closed contact, like a car horn. It's not a key-in buzzer is it?
So why do they call it dome light supervision, anyway?
How'd that term come about? Who's doing the supervising?
Does give it a sound of importance, though.
Posted By: mo12v
Date Posted: September 27, 2005 at 10:02 PM
Relay will also BUZZ on some Dome Lights that Fade out
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MO
Don't Learn from Others Mistakes
You Might Be the One That Knows.
Posted By: dualsport
Date Posted: September 27, 2005 at 10:13 PM
Is that how they control the dimming function? I'd think using a transistor rather than a relay for that would have been better, but I guess that'd work too-
Posted By: redpeppers
Date Posted: September 28, 2005 at 1:49 AM
a transistor .....a cap....
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Where theres is a wire there's a way.
Posted By: thefivespeeder
Date Posted: November 15, 2005 at 8:36 PM
I know this post is old but it's not locked yet, so I was wondering if you could use a relay w/ the domesupervision wire to power cold cathods and leds the only light up when the dome light is on?
Posted By: dualsport
Date Posted: November 16, 2005 at 9:19 AM
Sounds straightforward enough- are you trying to get it so it only comes on with the domelight supervision output active and not when the door switches turn the dome lights on? You just need the details on what kind of setup you have and what you're trying to do.
Posted By: thefivespeeder
Date Posted: November 16, 2005 at 12:19 PM
i want the accents on everytime the dome goes on, door inputs, hand control, keyless, etc
Posted By: dualsport
Date Posted: November 16, 2005 at 1:59 PM
What voltage do your accents run on?
If it's 12V, can't you just wire them in parallel to the dome light bulb? I assume the LED's don't draw much current, so you probably don't even need a relay, if they run on 12V power.
Posted By: thefivespeeder
Date Posted: November 17, 2005 at 10:53 PM
well i plan on running 2 pairs of cold cathods too, i mean the car is an 05 so i want to try to stick to relays, but it seems that is the way most people do it
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