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Discussion Starter #1
I have to haul a wheelchair and need to have wires running into the closed trunk lid of my '05 Focus. I always get an alarm that the trunk is open. What wires back there do I need to connect or disconnect to make the car think the trunk is closed all the time?
 

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I have 2004 wire diagrams, and this might help you, if I review them and take a guess at what wire-trick or hack might work for you (?) but please let us know if your car is a sedan or a hatchback, or a wagon?

Another different idea is to port the external wheelchair wires thru a new "modified hole" in order to prevent the door OPEN caution light/alarm light. I guess you are currently CRUSHING/SMASHING these wheelchair wires when closing the trunk(?) -not good.

Please post back and let us know your thoughts. -Cheers!
 

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Discussion Starter #3
Thanks - it's a sedan.
But even when I remove the 'squished' wires and close the trunk, the light still comes on. I think I've got something out of whack back there.

Maybe it's a door? Is there a way to check which place is actually causing the alarm?
 

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If you wedged the trunk lid to then be out of adjustment or even twisted the rubber stops in the corners you could have done that. Look at the work that happened to make the light come on. Or somebody tied into the wrong electrical there, you need a fully standalone system run there to not pirate power off anything to do with the trunk latch. To do it right you wouldn't even need to involve the trunk lid at all, the wiring would go into car lower down on the transom somewhere like mentioned by Marde in post #2.
 

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...Maybe it's a door? Is there a way to check which place is actually causing the alarm?
The short answer is no. You can not tell which door is causing the alarm. The longer answer is yes. You can figure out which door is causing the alarm, but it will take some technical skills, a multimeter, and a wire diagram or two.

Each door is monitored by a circuit (a switch) and a module called the GEM. When a door is opened, that door switch connects a circuit "to ground". With this "it goes to ground" rule, you can figure out which door switch/es are not operating normal; if using a meter and wire diagrams.

For a basic-easy test for the truck switch, try this:
Open the trunk and ensure the light inside the trunk is working. Now, fold down the rear seat back, so you can see inside the trunk space. Close the trunk and then look inside to see if that light is still on, is it?

Side note: You also need to learn how to close (aka spoof) each of the 4 doors "door jam switch" using your finger, or any tool.


...Look at the work that happened to make the light come on. Or somebody tied into the wrong electrical there, you need a fully standalone system run there to not pirate power off anything to do with the trunk latch...
That did not cross my mind. Maybe somebody messed-up some of the car wiring when adding his wheelchair wiring. Good point.
 

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Discussion Starter #6
Well, now we're getting somewhere. First off, this is an '05, I love her at 110,000 miles (and with all original brakes) but I'm not ready to get into something complicated.

But I now know, that a circuit is closed to make the dash light come on. I also figure that my trunk lid is probably askew and all I really want to do is get that (door upen) light out on the dash. It doesn't bother me, but when someone else uses the car it drives them nuts.

So.....
Which wire do I need to 'snip' to keep that circuit open, and is it on the lid or down above the bumper?
 

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...at 110,000 miles (and with all original brakes) but I'm not ready to get into something complicated...
Some specialty shops offer FREE brake inspections. Free or not, I highly recommend you get the brakes checked-out ASAP.

...
For a basic-easy test for the truck switch, try this:
Open the trunk and ensure the light inside the trunk is working. Now, fold down the rear seat back, so you can see inside the trunk space. Close the trunk and then look inside to see if that light is still on, is it?...
Jeff, Did you perform this test, quoted above?


...
So.....
Which wire do I need to 'snip' to keep that circuit open, and is it on the lid or down above the bumper?
Before I tell you about the wiring... you need to reconsider making physical alignment adjustments to your trunk deck lid to correct the problem IF that is the problem.

Next: the "rule" of circuit "closed to ground" (aka connected to ground) when the doors are opened is only true for the doors. The same rule is OPPOSITE when talking about the 5th door in hatchback, wagon and sedan.

Your sedan deck lid circuit is always closed to ground (aka connected to ground) while the truck deck lid is shut, and is electrically OPEN to ground when the truck deck lid is opened.

This Ground-or-no-ground signal is indirectly generated by a relay located inside the deck lid. The name of this relay is the Luggage Compartment Lid Release Relay. The signal is then sent to the GEM located near the front of the car. I do not want to tell you how to do this hack-modification because it requires personal car owner choices and technical savy. I would much prefer to tell you OR suggest that you fix the problem properly as opposed to a hack.

I will tell you that the truck lid OPEN verses CLOSED signal terminates at the GEM at connector C201a Pin#22.

Gd Luck
 

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Discussion Starter #8
Never have had a light in the trunk.
And why all the mystery? Does anyone really know how to disable the trunk open circuit?
 

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Never have had a light in the trunk.
There should be a light in the trunk space, but your's is obviously burnt-out, or not working for other reasons.

If this is not true, I need help from other sedan owners (2005-2007).

And why all the mystery?
I did not place any mystery into your situation. I said that modifying your car wiring (to prevent the 5th door ajar alarm) would require a unique solution AND any of these modifications requires a personal decision about how to do this. There are many different ways to do it, and it is not good for me to tell you how it should be done. I can think of a few ways to disable the alarm of this 5th door and/or all doors. But YOU need to get involved to decide what method, what electrical hack is best for you.

Does anyone really know how to disable the trunk open circuit?
Yes. I do. With all hack-modification methods put aside, I recommend you reconsider proper troubleshooting, and a proper fix.

The 5th door wiring/circuits are a little tricky. If I was doing a 5th door sedan electrical hack, I would need some "hands-on" time to ensure the hack was done properly.

The easier or more typical method is to repair the system, without any modifications.
 
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