louibluey
Well-Known Member
- First Name
- Joe
- Joined
- Dec 21, 2020
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- 60
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- Location
- NY
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- FE "Louibluey" GB
- Occupation
- retired
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- #76
I was planning to study and test the latch motor today, but with the so simple solution of a string tied to the latch release lever, I guess that is it for now. (Emergency Frunk Release). Also, on further thought, it might not be best practice to put a small 12V lead acid battery in the bumper in case of a fender bender, where it might short and get hot, possibly catching on fire, or serving as an ignition source post crash.
Just wanted to share some photos of the release latch motor. So, this is the part that supposedly gets operated/powered by those two wires (Red/Black) in the bumper opening if the LVB is flat (discharged or dead). The reason polarity is important is because it is a small DC motor that needs to turn the little gear box in the right direction to pull that white bar that moves the lever (the 2021 motorized version of a solenoid from last century). Presumably it is a 12V motor because you can use your jump source to open the frunk. Not sure about the two pull issue. The string that pulls on the lever has to be pulled twice, just like the cabin handle. No surprise there, because this latch motor system is pulling mid way (well more forward) on the very same cable.
BTW, a subject for another thread later, but the under the hood fuse box is really strange. on the outside are two side by side giant multi pin connecters, the kind with the lever / lock arms. To get to the fuses, you leave those to connectors alone, but the box opens in half and the fuse array is on then inside of the 1/2 box that comes off (fuses opposite side, same half of the connector side). One odd part is there are several main LARGE fuses on the first 1/2 of the box that stays with the chassis, and pulling the box apart, removes power from the fuse box 1/2 with the fuses.
So, with all that disconnecting going on, first I pulled the 12V LVB negative terminal and taped that cable to the bar, so that it did not fall back and touch the battery neg. terminal. At that point I realized I had a LVB dead scenario, but the two wires in the bumper still read about 47k ohms (47,000 ohms), way higher than I would expect for a motor coil. So, at least in that scenario, I doubt the frunk motor latch is operative from the black and red wire in the bumper anyway! (although, I suppose it is possible that 12V would power an electronic circuit in the front trunk release relay module that would set up a system to power the motor)
Just wanted to share some photos of the release latch motor. So, this is the part that supposedly gets operated/powered by those two wires (Red/Black) in the bumper opening if the LVB is flat (discharged or dead). The reason polarity is important is because it is a small DC motor that needs to turn the little gear box in the right direction to pull that white bar that moves the lever (the 2021 motorized version of a solenoid from last century). Presumably it is a 12V motor because you can use your jump source to open the frunk. Not sure about the two pull issue. The string that pulls on the lever has to be pulled twice, just like the cabin handle. No surprise there, because this latch motor system is pulling mid way (well more forward) on the very same cable.
BTW, a subject for another thread later, but the under the hood fuse box is really strange. on the outside are two side by side giant multi pin connecters, the kind with the lever / lock arms. To get to the fuses, you leave those to connectors alone, but the box opens in half and the fuse array is on then inside of the 1/2 box that comes off (fuses opposite side, same half of the connector side). One odd part is there are several main LARGE fuses on the first 1/2 of the box that stays with the chassis, and pulling the box apart, removes power from the fuse box 1/2 with the fuses.
So, with all that disconnecting going on, first I pulled the 12V LVB negative terminal and taped that cable to the bar, so that it did not fall back and touch the battery neg. terminal. At that point I realized I had a LVB dead scenario, but the two wires in the bumper still read about 47k ohms (47,000 ohms), way higher than I would expect for a motor coil. So, at least in that scenario, I doubt the frunk motor latch is operative from the black and red wire in the bumper anyway! (although, I suppose it is possible that 12V would power an electronic circuit in the front trunk release relay module that would set up a system to power the motor)
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