led ghost light relay
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=134929
Printed Date: May 01, 2024 at 1:12 AM
Topic: led ghost light relay
Posted By: ponchonutty
Subject: led ghost light relay
Date Posted: September 24, 2013 at 7:16 AM
OK so I've been doing 12v installs for 17 years but for why I don't know why this has me stumped. The truck is a 2008 GMC Yukon. The lights pull too much amperage and the trucks dome lights (gray wire pin 5 white plug at BCM) doesn't like it and the result is that no lights or sporadic operation. I installed a relay and they work fine except the truck has the "soft" on/off feature on the lights causing the relay to buzz when trigger. How do I keep the relay from buzzing????
Replies:
Posted By: oldspark
Date Posted: September 30, 2013 at 11:38 PM
A diode with cap across the relay coil may help - maybe a 4700uF or larger?
Posted By: powerslave
Date Posted: October 26, 2013 at 2:44 PM
The reason it buzzes if because of the soft on/off feature. The coil pulls the switch in th relay, and at low voltages it will buzz. Try using an electronic relay instead.
Kind of like how your car solenoid clicks on and off when your battery is about to die; only much faster with the smaller relay.
Posted By: oldspark
Date Posted: October 26, 2013 at 6:29 PM
You don't want any relay energised by PWM, hence tye filter solution.
If the new lights/LEDs are also to dim, then a MOSFET or transistor could be used. (SSRs are more expensive and may fail. They are designed as relays, not fast switches.)
Posted By: user error
Date Posted: January 15, 2014 at 1:42 AM
Man everyone is going at this the hard way drop a capacitor across the supply and ground posts of the relay and the issue will be solved the cap will charge on the first pulse and fill in the blanks as the pulse goes in and out till it gets full power... Had the same issue wiring my aux reverse lights with triple triggers... been working over a year now no issues...
Posted By: oldspark
Date Posted: January 15, 2014 at 6:35 AM
Without a diode? (Else resistor.)
Amazing!!
Posted By: user error
Date Posted: January 15, 2014 at 12:34 PM
Re-read your post Oldspark... I missed the "cap" reference... Was half asleep when I posted that... I am running diodes on the triggers pre-relay however not on the cap... the cap is stand alone across 85 and 86
Posted By: oldspark
Date Posted: January 15, 2014 at 3:55 PM
Cool. I'll put that down to user error (ha ha).
But I agree, there is some overly complex and misleading reply info...
Whilst I am normally the one to expand, in this case I merely posted a (possible) solution and avoided the analog or PWM soft start complications.
And I figured I'd delay any buffered solution until after the big cap blew the softstart circuitry.
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