Powering an overhead DVD off dome light

[stones 10+ year member]

Need some training here..

In some vehicles they have that positive ground wire and constant power wire for the overhead dome light then a ground, basically three wires.

I am told i need a relay(spst) to use those wires to power an overhead DVD unit.

Now on the relay there is the constant power input and the remote on input, do I connect the positive ground to the remote on input(pin86) then ground it to chassis(pin85)?

Will that work?.

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[Slody4Futbol 10+ year member]

no... just run new wires... those wires are usually very small... and using a relay... and just wiring all the pins to the existing wires would defeat the purpose for a relay... just run the wires... if you can put the overhead up then you can run wires... mounting them is the hardest part

 

[stones 10+ year member]

I'm not worried about wire size as these units are only rated for a 3amp maximum current draw.

So far I've just been splicing into the factory decks power wires and running them up to the DVD unit but yesterday I had a 2004 Ford Freestar come in and I didn't have any info for the factory wiring harness colors and my DMM didn't have small enuff pins to stick into the harness to find the which was which, so long story short I used the dome lights constant power to power the DVD, this is a ghetto way to do it and I would like to know once and for all how to use those dome lights power wires properly.

 

[Slody4Futbol 10+ year member]

well a relay won't help you if you're not running a new power wire up to the unit... just figure out which one is constant... and which one is ground... and use those... there is not a true switched wire that comes on with the ignition... there is a wire that will either be positive switched or negative switched when a door is opened to turn the domelight on... so use your DMM and figure out the 2 wires... you will have to put ignition and constant together... you could also use the fusebox if you didn't want to try to find the wires behind the headunit... but the metra harness is a 5520 if you have it in your shop or have access to it... but the constant wire is gonna be a big thick wire in one of the corners of the harness... the switched ignition... is diagonal from that wire... in the middle set of wires... it's in 1 of the 1st 2 rows...

 

[stones 10+ year member]

OK, thanks //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[UndercoverPunk 5,000+ posts]

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