pos trigger to neg output?

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=115411
Printed Date: July 12, 2025 at 10:42 AM

Topic: pos trigger to neg output?

Posted By: rodriik
Subject: pos trigger to neg output?
Date Posted: August 01, 2009 at 3:02 PM

Hi guys. I am trying to get my positive door/dome light trigger to output a negative signal to control the maplights on a new Gentex rearview mirror. My car is a 2009 Jeep Wrangler.

The Gentex mirror came with a relay box that had a switch for vehicles with + door triggers, and it worked, but the thing was really loud when turned on/off and it buzzed when the dome light would fade out. I cut the box out and got a solid state relay to replace it, but I can not get the thing to work right. Can anyone tell me the best way to wire it?

I can only get it to work opposite the dome light or stay always on. Do I need to use two relays?

thanks

Replies:

Posted By: howie ll
Date Posted: August 01, 2009 at 5:12 PM

Flip it with a transistor Mr. Idiot has the answer.

Posted By: mikvot
Date Posted: August 01, 2009 at 5:24 PM

Or just use the neg. door triggers in the vehicle, and diode isolate each wire you use. Just use the wires you want to actually turn on the lights.

LF Latch	VIOLET OR VIOLET/WHITE	(-)	IN HARNESS IN DRIVER KICKPANEL
RF Latch	VIOLET/WHITE	(-)	IN HARNESS IN PASSENGER KICKPANEL
LR Latch	VIOLET / YELLOW OR VIOLET GRAY	(-)	IN HARNESS IN DRIVER KICKPANEL
RR Latch	VIOLET / YELLOW	(-)	IN HARNESS IN PASSENGER KICKPANEL
Trunk Trigger	VIOLET/ORANGE	(-)	IN HARNESS IN PASSENGER KICKPANEL

Posted By: rodriik
Date Posted: August 02, 2009 at 5:29 PM

howie ll wrote:

Flip it with a transistor Mr. Idiot has the answer.

How would I do that? I'm using a Hella H41773001 like this https://cat.hella.com/hella232/jsp/details/content/Object.jsp?editedObject=¤tObjectid=CA@USAData@PR@H41773001&type= &updateObjectid=true&backlinkId=1249246688791¤tObjectIndex=&SearchResultList==

thanks

Posted By: rodriik
Date Posted: August 02, 2009 at 5:31 PM

like this https://www.summitracing.com/parts/HLA-H41773001/

Posted By: howie ll
Date Posted: August 02, 2009 at 5:38 PM

This is almost too simple to answer but that relay will have 4 or 5 terminals. 85, 86, 87, 30 and possibly 87a. Ignore 87a.

Take your domelight pos feed to 86,

ground to 85 and 30,

Neg output from 87 to the Gentex mirror, or even easier to modify what Mikvot says, take one or all of the door triggers, if you take more than one, diode them together with the bands towards the door triggers and feed them to your Gentex mirror.

That relay shown is $40 for $4 go to Radio Shack

Posted By: rodriik
Date Posted: August 02, 2009 at 6:27 PM

howie ll wrote:

This is almost too simple to answer but that relay will have 4 or 5 terminals. 85, 86, 87, 30 and possibly 87a. Ignore 87a.
Take your domelight pos feed to 86,
ground to 85 and 30,
Neg output from 87 to the Gentex mirror, or even easier to modify what Mikvot says, take one or all of the door triggers, if you take more than one, diode them together with the bands towards the door triggers and feed them to your Gentex mirror.
That relay shown is $40 for $4 go to Radio Shack

Thanks, but that is the way I tried to do it before posting here, and it doesn't work. Could it be because the relay is solidstate?

Posted By: rodriik
Date Posted: August 02, 2009 at 6:46 PM

It stays on permanently when connected in that manner.

Posted By: rodriik
Date Posted: August 03, 2009 at 3:57 PM

Is there anyone that actually does know how to hook up a solidstate relay so the polarity is reversed?

Posted By: mikvot
Date Posted: August 03, 2009 at 8:15 PM

First off, start your own thread.
Second, year, make, model of vehicle
Third, what model of autopage

Posted By: rodriik
Date Posted: August 03, 2009 at 9:38 PM

OK guys, I decided to just invert the polarity before the relay with an inverting transistor circuit or IC inverter.

My brother has a box of ICs in his room like this...https://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=TC4S69FT5LFT-ND . Would that thing work in my car for my use?

Or would it be better to get some transistor and resistors and stuff? Is something like this already made as a preassembled unit?

thanks again