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DIY: Bioweapon solution for Cabin air filter

Here is a summarized/ comprehensive write-up on the already covered thread on adding a very close Bioweapon defense mode option to your S. This is to provide a DIY without scavenging through the Original Thread's 13+ pages of conversation.

Anything not covered in this will most likely be answered somewhere in the original thread:
How to add a HEPA filter to your non-Bioweapon facelift Model S!

Purchase links for the materials will be at the bottom!

If you have the refreshed S (with the smaller Frunk as pictured below, this will work for you)

Install Difficulty is a 2/10


1.You want to pop/pull off the under hood plastics - Left, Right, Upper, Lower
The lower panel is held on very tight by a clip located above the Tesla Logo. apply even pressure close to the clip on both sides of it and it will pop off.​

2. Pull out the carpet liner from the rubber weatherstripping UNCLIP YOUR TWO HARNESSES for the release and light, and set aside.

Screen Shot 2018-03-11 at 2.17.30 PM.png

3. There will be 12 bolts overall holding the funk in place. I was able to easily run those out with an electric driver.
You can now pull the frunk up to remove the rubber grommet holding the wiring harness in place. Feed the two wires through and set the frunk off to the side as well.

4. With the frunk removed you will see the AC intake open with no filter in place! CONGRATULATIONS, Tear-down is complete!


5. Take your 14x27.5x1 MERV 13 or better filter and cut out the Charcoal pad to the size. I recommend affixing it to the rear of the Filter with some tape to hold it in place during installation.

6. With the air-flow arrow and charcoal pad aiming TOWARDS the cabin, put the top of the filter in first and slide in the bottom.

Looks fancy huh? o_O

7. Now Reassemble:
  1. Feed the grommet through the frunk and drop it back down into place.
  2. Thread the 12 bolts back into place, Start the upper middle 3 bolts first as they are the ones that lined the airbox up easiest for my case. Thread all bolts correctly before tightening down- If using an electric driver like I did, snug the bolts to the first "hammer click" and NO MORE or you may risk damaging the part.
  3. Put your liner back into the frunk and hook up the release and light harnesses.
  4. Worst part... re-tuck the carpet liner under the weatherstripping. This isn't hard but it's tedious.
  5. Reinstall the plastics starting from the bottom panel -> side panels -> top panel.


Now for the way to get the software to enable this to work as of Q1 2018

  1. Turn on the AC if not already turned ON of course
  2. Enable all the vents
  3. Enable FRESH AIR mode and have the fan set to 1-10 (Not 11 as it will disable fresh air mode)
  4. Here's the trick. USING STEERING WHEEL CONTROLS for the Fan Speed, run the speed of the fan to 11 using the dial. It should enable fresh air mode while pressurizing the cabin.
  5. Confirm- Open the AC menu on the touchscreen and see if it says all vents are still open, fresh air mode, fan setting 11

You've now pressurized your cabin with Marv 13 (or better) and charcoal filtered air! This is essentially better than 99% of the Filtration systems on any vehicle on the road, along with a very close equivalence to the BioWeapon Defense mode!


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Great instructions. Got it done in no time. I was unable to get the fan to stay at 11 with fresh air. When I change it to 11 on the wheel, it puts recirculation on. Maybe they changed the software?
Fan speeds of 10 and 11 have required recirculation to be turned on since at least late 2017. My first S, still on V8.1 did this.
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