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Finally a solution for \'21-23 ID.4\'s to precondition the HV battery in cold weather for faster L3/fast charging!
All units shipped after 1/10/26 include monitoring ability with a cell phone or tablet/pc. Just plug the usb-c cable into your phone and use a serial/usb terminal app to watch activity (see pics above).Takes about 30 minutes to install for someone with auto repair experience. Once installed, just plug in the USB-C cable to an outlet in the vehicle and the HV battery will start preheating. Takes 15-30 minutes depending on the battery and outdoor temp for max L3 charging rate.Installation instructions below and on the vwidtalk forum. Read thoroughly before starting!
- Need USB-C cable, 1.2M/5\' recommended. Tools needed - pliers, T20 torx screwdriver or rachet.
- The on/off switch on the module should remain OFF.
- Keep car off and keys inside the house so the vehicle does not wake up.
- Move passenger seat back to give yourself room to work.
- Empty glovebox then lower it by pushing tabs up (see pic).
- Remove and set aside the glovebox gear so it does not get knocked out by accident.
- Remove the 4 T20 torx screws holding the plastic glovebox ceiling in place.
- Pull down from the front (or use a screwdriver above the glovebox release tabs) and unsnap the plastic ceiling; set aside.
- The HVAC control module is to the left.
- Unclip and rotate the white handle up to unlock the wiring harness; then pull the wiring connector to the left and out of the way. You are NOT clipping into this wiring connector; it is being removed in order to slide out the module.
- Push the plastic tab to the right (see pic) and pull the HVAC module towards you.
- Remove 2-3 inches of of the cloth tape on the wiring harness closest to you at the top to access the wires.
- Look for the light brown and light blue wires twisted together. Put the light brown/orange wire inside the 2 pin wiring connector and the light blue/aqua wire in the outer tray. Snap the connector together and squeeze tight with pliers. Then put the brown wire in the 1 pin wiring connector and squeeze together.
- Slide the HVAC module back into place.
To use: While the car is on/driving, connect the USB-C cable to an outlet in the center console for 10-30 minutes before L3/fast charging (it takes longer to pre-heat the battery as the outdoor temps drop further). Or plug into your phone to monitor acitvity with a serial terminal app running at 115200.
