200 ma enough?
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=118828
Printed Date: May 13, 2025 at 12:35 AM
Topic: 200 ma enough?
Posted By: hum dinger
Subject: 200 ma enough?
Date Posted: December 26, 2009 at 5:05 PM
My car alarm has a 200mA output for trunk release. Is that enough to use directly or do I need a relay? Thanks
Replies:
Posted By: hum dinger
Date Posted: December 26, 2009 at 5:06 PM
I forgot. It's in a 2006 Hyundai Elantra.
Posted By: howie ll
Date Posted: December 26, 2009 at 5:15 PM
How is the Elantra's trunk release wired? if the switched side is pos, no if neg yes, though you should still meter those outputs to see the draw. assuming 2 wires to the switch.
Posted By: t&t tech
Date Posted: December 26, 2009 at 5:16 PM
Do you have an electronic switch that releases the trunk ?or is it mechanical, and you are going to do the conversion? ------------- COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Posted By: howie ll
Date Posted: December 26, 2009 at 5:27 PM
I thought all US market vehicles from around 2000 had a built in solenoid trunk release with a switch at the front.
Posted By: i am an idiot
Date Posted: December 26, 2009 at 5:32 PM
 | Trnk Release | | YELLOW/BLACK | | (+) | | AT TRUNK RELEASE SWITCH |
Posted By: howie ll
Date Posted: December 26, 2009 at 5:37 PM
Thanks Mr. I. relay obligatory, take your trunk output to 85, 12volt+ constant fused at 15amps to 86 and 30, 87 to yellow black
Posted By: hum dinger
Date Posted: December 26, 2009 at 6:22 PM
acording to my chart it says it's a white wire that is a negative. Located at the Body control module. It should be electric because it does it from the stock remote control. I know how to change polarities with A relay. I'm was just curious about how many mA the truck pop needs typically. the output from the alarm is only good for 200mA.
Posted By: howie ll
Date Posted: December 26, 2009 at 7:00 PM
At a guess, what you have once you test it is the trigger wire for a remotely located relay which enables the solenoid. Just cut the wire, set your DMM to amps hit the trunk lead switch and away you go. If it doesn't work turn around the test leads. The other way would be to use a Snap-On test light. Ground the croc clip and probe the other end to the white wire. If that releases the trunk, just attach your trunk release wire to it and job done.
Posted By: hum dinger
Date Posted: December 27, 2009 at 4:01 PM
the problem is that the trigger is so fast it dosn't register on the meter long enough to check amps. Even if you holf the trunk release button it just pulses real fast.
Posted By: KPierson
Date Posted: December 27, 2009 at 4:24 PM
Supply the (-) current directly from ground through the meter. This will cause the solenoid to latch and you should be able to read the current. Also, for short pulses disable auto ranging, it will allow you to read signals faster. ------------- Kevin Pierson
Posted By: howie ll
Date Posted: December 27, 2009 at 5:50 PM
Blimey over here you can buy a DMM with hold for under $50, its enough for this job.
Posted By: chriswallace187
Date Posted: December 27, 2009 at 10:38 PM
Honestly, I think you should just verify that you've got the correct trunk relase wire and connect it. I've never yet seen an alarm aux output that couldn't activate a relay circuit on a car.
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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two
Posted By: hum dinger
Date Posted: December 28, 2009 at 7:05 PM
Thanks guys, Got the alarm installed and it works great. You were right chriswallace187, it works right off the alarm without a relay. There is one problem though....when I dissarm the car it unlocks the doors but it also pops the trunk. Remotely poping the trunk does NOT mess with the door though. Any ideas?
Posted By: KPierson
Date Posted: December 28, 2009 at 7:13 PM
It may help if you tell us what alarm you put in the car - only one guy on this site has a crystal ball and he has yet to post in this thread.
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Kevin Pierson
Posted By: chriswallace187
Date Posted: December 28, 2009 at 7:15 PM
It won't surprise me at all if this is a Scytek alarm, since I've had exactly the same problem with one.
Try using a separate relay activated by the trunk release output, wired as follows:
85: (-) trunk release output from alarm
86: constant fused 12v+
87: ground
30: trunk release wire on car
That worked in my case...I assumed that for whatever reason the unlock output and trunk release output weren't isolated very well on the pc board, and there was just low enough resistance to ground to activate the trunk release circuit on the car when "unlock" was pressed.
Definite design flaw in that module(and I tried a spare brain with the same results) but it was easy enough to work around.
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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two
Posted By: hum dinger
Date Posted: December 28, 2009 at 7:15 PM
Sorry, I was just coming back to add that info but your faster than I am haha. 2007 Hyundai Elantra Autopage C3-RS665-2W Thanks
Posted By: i am an idiot
Date Posted: December 28, 2009 at 7:53 PM
The crystal ball is down at the moment. Sorry.
Posted By: howie ll
Date Posted: December 29, 2009 at 2:46 AM
Er I think we just came round full circle, that's what I suggested on the previous page Chris!
Here's an alternative though to completely isolate it:-
Trunk trigger from alarm to 85, constant 2amp fused to 86, existing wire, car side 87a, trunk side 30 and good ground to 87.
Posted By: hum dinger
Date Posted: December 29, 2009 at 5:59 PM
Do you think it's getting the stray current from the BMC of the car? If I'm understanding your wiring suggestion correctly. I would have thought it would be in the alarms brain.
Posted By: chriswallace187
Date Posted: December 29, 2009 at 7:24 PM
No, the stray current's going from the alarm to the BCM, where it activates the trunk release circuit. Most likely that's just the wire from the release switch on the door/dash or wherever, and the BCM looks for any ground signal whatsoever.
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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two
Posted By: hum dinger
Date Posted: December 29, 2009 at 8:07 PM
Thanks for the suggestions guys. Wired it like you suggested Chris, it was easier than the other suggestion so I thought I would try it first and it worked perfect. I'm sure the other way would have worked also, just a more work. Thanks
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