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Trunk relase doesnt work

Dred 25

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Hi. Im new to this forum. Need your help guys. My problem is trunk doesnt openning. Button inside, remote and bumper switch doesnt work, only blinks when button release on keyfob. No relay click sound on footwell. Wires on trunk all ok, no splice. Any inputs on how to fix? Thanks.
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Skye

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Welcome to the forums. :fistbump:

https://www.mustang6g.com/forums/threads/introduce-yourself.6728/

I was curious how the latch was powered, which fuse supported the latch.

It isn't documented in my Owners Manual. The fuse position is labeled as "not used". But from one YouTube video, several thread posts, and the attached, internal fuse panel, fuse position 16 powers the release latch. Have you checked that fuse?

The panel I'm referring to is in the interior, right side, near the door and where someone would place their feet. I've attached some references.

Fuse #16 is a 15A fuse. It sits opposite of fuse #34.

bcma location 001.jpeg


bcma location 002.jpeg
 

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Dred 25

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Thanks for the reply. Fuse #16 15a is good. Cannot open the trunk unless pull the yellow tab. No relay click
 

Skye

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What is the history of the car? Are you the original or new owner?

Any water or accident damage?

Has this latch always been faulty or is this a new problem?

With someone operating the interior button or the fob, have you confirmed power is actually getting to the deck lid latch area?
 
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Dred 25

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Im the second owner, I already replaced new latch. No power i think from bcm to rear latch since it has no clicking relay sound from bcm.
 

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Dred 25

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No water damage or accident. Do I have other things to check in bcm connector?
 

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The thread is new and the day here in the US is still young. Other Members might have better ideas. The only other action I can recommend is to begin physically tracing and checking wires all the way back to the BCM in the interior.

In the trunk, there is a second BCM, BCM-B, on the same side of the vehicle as BCM-A. Your tracing might initially lead you to this general area, and ultimately back to the fused connection at interior BCM-A.

From my references, BCM-B has no fuses. Just two, large physical connectors, supporting wiring and functions in the rear of the car. While checking, I'd confirm these two connectors are seated well.

bcmb location 001.jpeg


bcmb location 002.jpeg


bcmb photo.jpg
 

ORRadtech

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What year is the car? 15-17s erre known to have wire issues between the body and trunk lid within the harness. These are not always visible to the eye even if the harness is stripped away.
All "relays" within the BCM are solid state, you won't hear a click.
I think you will find that you need a wiring diagram from a factory service manual and a DVOM and start methodically tracing wiring either from the BCM back or the lock latch forward. Personally, I'd start at the BCM.
 

NightmareMoon

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^ this. The 15-17 wires were too short and would get repeatedly stretched out. There was a recall in the US. I doubt it would be visible to the naked eye. Mine failed very early on.
 

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If a convertible and the valet mode is active then the key/button will not unlatch the trunk until the valet code is deactivated.
 
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Dred 25

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Thank you very much for replies. I Check all wires in the trunk, there is a cut and i connect it all. Check for continuity still not working. Maybe I will trace 4 wires from latch to front bcm check for continuity. I would like to ask if there is a setting in forscan that I can check?
 
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Dred 25

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Also need to know if there is realy no click sound in bcm when opening trunk? When door lock button push there is a click sound in bcm
 

Cobra Jet

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If the harness is broke - you’re not going to get anything at all - nothing from a remote attempt and no “click” from any testing. Once the harness wire or wires in trunk is broken, all continuity ceases to exist as well as any function to operate XYZ on the same harness.

You have to pop the trunk lid somehow and the manually inspect the harness. You can’t just look at it from the exterior casing, you actually have to remove the black conduit and then look at each wire inside of that casing and trace them one way or the other to find the break(s).

There was another thread on here recently with a convertible owner who could not get into their locked trunk due to a no power issue. I believe they eventually got in though…. I can’t recall the member at the moment but just search for “trunk key” or “trunk access” those terms should find the thread (it was posted within the last month or so).
 

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Hi. Im new to this forum. Need your help guys. My problem is trunk doesnt openning. Button inside, remote and bumper switch doesnt work, only blinks when button release on keyfob. No relay click sound on footwell. Wires on trunk all ok, no splice. Any inputs on how to fix? Thanks.
Try pushing down on the trunk lid as you push the bumper release button...
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