Demand-lighting circuit
Thread Starter
Joined: Oct 2007
Posts: 350
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From: Huntsville, AL
Demand-lighting circuit Hi guys, I want to wire in LEDs under the hood, but I want to tie it in via a toggle switch to the demand lighting circuit. Basically I want it to have power when the key is turned but will turn off with the interior lights after the delay if I accidently leave it on. Where would the place to tap into that either in the interior or under the hood? I hope that makes sense. Thanks in advance.
Q
Q
TECH Enthusiast
Joined: Jun 2004
Posts: 597
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Why would you want to light the engine bay with the hood closed?
anyway. should be able to do that from the drivers side fuse box. Just have to locate a fuse that is handled by the RAP system. Tie it in there, likely have to find that wire on the back side as there isn't alot of work room on the front. run that new wire out through the firewall and use a relay to control the LEDs in the hood with a direct battery tap.
RAP isn't part of the lighting, but would certianly shut off when you open the door as its the Radio/Window power circuit.
To tap into the lighting would be easier. Pull the Headlight control module out and find the wire that receives power when you turn the brightness wheel all the way up. tap into that wire for your LEDs. No real need for a fuse since the lighting circuit's fuse will be protecting the new stuff as well.
anyway. should be able to do that from the drivers side fuse box. Just have to locate a fuse that is handled by the RAP system. Tie it in there, likely have to find that wire on the back side as there isn't alot of work room on the front. run that new wire out through the firewall and use a relay to control the LEDs in the hood with a direct battery tap.
RAP isn't part of the lighting, but would certianly shut off when you open the door as its the Radio/Window power circuit.
To tap into the lighting would be easier. Pull the Headlight control module out and find the wire that receives power when you turn the brightness wheel all the way up. tap into that wire for your LEDs. No real need for a fuse since the lighting circuit's fuse will be protecting the new stuff as well.
Last edited by Nova5; Mar 9, 2009 at 08:41 AM.
Joined: Nov 2003
Posts: 11,334
Likes: 347
From: Jacksonville, FL (originally from Toronto Canada)
I agree with Nova5... wouldn't it be easier to install a mercury switch so that the underhood light only goes on when the hood is open?
On the other hand, don't use the dimmer wire from the dash switch because it works on a voltage reduction that doesn't work well with LEDs. You also don't want to use the courtesy light power because although it will go off when the BCM "goes to sleep", it will be on all the rest of the time (like the map lights are available all the time - same power circuit).
On the other hand, don't use the dimmer wire from the dash switch because it works on a voltage reduction that doesn't work well with LEDs. You also don't want to use the courtesy light power because although it will go off when the BCM "goes to sleep", it will be on all the rest of the time (like the map lights are available all the time - same power circuit).
Joined: Nov 2003
Posts: 11,334
Likes: 347
From: Jacksonville, FL (originally from Toronto Canada)
You're right of course but I wanted to make sure he didn't use the dimmer circuit. Most people don't realize there's a separate circuit when the dimmer is turned all the way 'til it clicks.
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Verdad Gallardo TECH Enthusiast
Joined: Jun 2004
Posts: 597
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flickering an LED isn't harmful to it, so a merc switch would work well enough.
Mount the merc switch so when the hood is opened on a slight downhill incline is at about 25-30 degrees. When closed the angle will be so severe that the chance of a bump tripping it will be negligible.
Mount the merc switch so when the hood is opened on a slight downhill incline is at about 25-30 degrees. When closed the angle will be so severe that the chance of a bump tripping it will be negligible.
Last edited by Nova5; Mar 9, 2009 at 04:14 PM.