Electric Frunk (Variant B MARK 3)

This is the installation guide for Tesla Model S Electric Frunk (Variant B MARK 3) from EVOffer.


Touch Screen

Tesla Official App


Key Fob






Height Setting (Initialization)

Adjust the liftgate to your desired height. Press and hold the button on the control unit for about 5 seconds, until you hear a beep (Make sure the buzzer is connected).

Speed Setting

When the liftgate is in open state, press and hold the button on the control unit. You will eventually hear two long beeps (speed 2), three long beeps (speed 3), four long beeps (speed 4), up to six long beeps (speed 6). Release the button after you hear the speed you want to set. The slowest speed is speed 2 and the highest speed is speed 6. The factory default is at speed 4.

Packing List

  1. Lock Assembly with Latch Motor

  2. Replacement Strut x 2

  3. 3M Tape

  4. Cable ties

  5. Waterproof Control Unit

  6. Signal Wire

  7. Fuse Cable

  8. Major Wire Harness

  9. Buzzer


  1. 10mm Hex Socket

  2. 13mm Hex Socket

  3. Short Wrench (for removing the latch unit)

  4. Small Flat Head Screwdriver


Step 1 - Removing Trim Pieces

Remove the cover panel pieces. Pull them out with bare hand. Start with the top, then the side, and finally the front one.

Step 2 - Remove Frunk Well

Behind the frunk liner, unplug the button connector and the LED connector, then pull out the frunk liner.

Remove the black piece indicated. There are 3 push pins to remove first. After that, gently release the tab on both side and then take out the piece.

Also take out the air inlet piece.

Remove all the 10mm hex screws that you see from the frunk well. Also remove the two push pins that are on the front of the frunk well. Now you can take out the frunk well

Step 4 - Replacing the Struts

Now we will remove the struts. Let's start with the left side of the car. Insert a flathead screwdriver into the channel as shown in the picture, and then with one hand pushing up the hood a bit, pull the strut out.

Repeat the same thing to the lower ball joint.

Now the hood might fall so be caution. Insert one of our strut into the lower joint (the side of the strut that near the wire). Don't insert it to the upper joint yet, because it will make it more difficult to remove the right strut.

Now go ahead and remove the right strut from the upper joint. After you remove the upper joint of the right OEM strut, the hood will be completely freed, so use a hand to support the hood. Now go back to the left side of the car and mount the left strut to the upper joint.

Remove the right OEM strut completely, then do the same thing as you did to the left side of the car.

The struts are successfully installed. Run the wires beneath the trim piece to the location where the battery is located, and then attach the connectors to the major wire harness.

Step 5 - Adding Latching Mechanism

Remove the 10mm hex screws as indicated in the picture. Be careful not to let the thick black washers that's behind the screw from falling off.

Unplug the connector that goes into the latch.

Remove the spring from the latch

Now it's time to attach our latching mechanism. Run the latching mechanism below the beam and to the front of the car. Don't run the latch wire above the beam as it will block the frunk well when you install everything back. Hook the bigger metal piece into the hole indicated

Also tighten the two 12mm nut with wrench, leaving around 3 threads from the wire end

Insert the rectangular hole of the smaller metal piece into the indicated location

Install our spring.

Now install the latch back into the car.

Step 6 - Connecting the signal wire

Now take out the signal wire. There are two connector pairs.

Unplug the OEM connector from the lock motor that is located on the right side of your car (if you are facing toward the car it's on your left side)

Connect one side of our blue connector pair to the removed OEM connector, and plug the other side of our blue connector back into the lock motor.

Now remove the OEM plug from the latching lock. Plug the OEM plug to one side of our corresponding connector pair, and the other side of our corresponding connector pair back to the latching lock. Make sure they are fully inserted.

On the other side of the signal wire, connect the black little connector to the 4pin connector from the major wire harness.

Now connect the brown connector from the major wire harness to the latch motor, and fix the latch motor by cable tie.

Run the emergency pull wire of the latch motor to somewhere accessible in case the frunk fail to open (usually behind the wheel well).

Step 7 - Connecting the power and ground

Get the small black wire that come with the fuse. Insect the metal end into the positive terminal of the 12V battery. You need to use a 10mm hex socket to loosen the terminal and insert the metal below the metal nut, and then tighten it again.

On the other side of the fuse wire, unplug the white plug, and connect the silver terminal from the major wire harness to the plug, then connect it back to the fuse wire.

Connect the ground (the golden spade terminal that come with the wire harness) to the indicated location, it's in the left side of the car, under a 10mm hex nut.

Step 8 - Finishing up

Connect the buzzer to the major wire harness by the 2pin connector

Connect the big plug from the major wire harness to the waterproof control unit.

The light on the control unit

Step 9 - Testing the system

Now the system is ready to be tested. We need to make sure the latch can be released after locking, so use your hand or a screwdriver, push downward on the latch to "lock" the latch. Then plug in the OEM wire back to the emergency button (On the little cover that you removed). Press the emergency button to make sure the latch release.

If the latch release, then the system is ready to be tested. Hold the black button on the control unit until you hear a beep to initialize the system. After initialize, press the emergency button to test the frunk closing. If the frunk close successfully, then go to open the frunk from the touchscreen to test the opening.

Software Update

Step 1 - Preparing Memory Card

Prepare a microSD with 32GB or below capacity. Make sure it is in FAT32 format.

Step 2 - Getting the Update File

Get the update file ready. The file would be provided by tech support if needed. Rename the file to update.yst and place it under the root of the microSD.

Eject it from the card reader afterwards.

Step 3 - Flashing the Update

Insert the microSD into the control unit. The red LED will be flashing rapidly.

Wait until the LED becomes solid and eject the microSD.

Complete! Test the System

The LED should be flashing constantly now and you are all set!

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