why is my Tesla Model S Original (2012-2020) rear window fogging up

Tesla Model S Plaid/Refresh (2021-present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

443 words

Problem Statement

Learn how to diagnose and fix rear window fogging issues in Tesla Model S (2012-2020). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component

HVAC

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Ensure the vehicle is powered off and parked in a safe location before starting any repair work.

Symptoms

•Rear window fogs up during cold weather or high humidity
•Difficulty in clearing the fog using the defrost setting
•Presence of moisture or condensation inside the vehicle
•Possible increase in cabin humidity or damp smell
•Noticeable fogging even with the HVAC system running

Diagnostic Steps

1
Inspect the cabin air filter for blockage or contamination.
2
Check for leaks in the vehicle’s weather stripping or seals around the rear window.
3
Test the HVAC system for proper operation of the defrost and air circulation settings.
4
Examine the rear window for any cracks or damage that may allow moisture to enter.
5
Monitor interior humidity levels using a hygrometer.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•Flathead screwdriver
•Socket set
•Vacuum
•Microfiber cloth

Parts Required

•Cabin air filter
•Weather stripping (if damaged)
•Glass repair resin (if applicable)

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Diagnostic Steps

1
Inspect the cabin air filter for blockage or contamination.
2
Check for leaks in the vehicle’s weather stripping or seals around the rear window.
3
Test the HVAC system for proper operation of the defrost and air circulation settings.
4
Examine the rear window for any cracks or damage that may allow moisture to enter.
5
Monitor interior humidity levels using a hygrometer.

Solution

1. Preparation

Gather necessary tools: flathead screwdriver, socket set, vacuum, microfiber cloth.
Ensure the vehicle is parked in a well-ventilated area with adequate lighting.

2. Replace Cabin Air Filter

Sub-steps:
1. Open the front passenger door and locate the cabin air filter access panel under the glove compartment.
2. Use a flathead screwdriver to gently pry off the panel cover.
3. Remove the old cabin air filter and clean the area to remove any debris.
4. Install the new cabin air filter (ensure it’s oriented correctly).
5. Reattach the access panel.

3. Inspect and Replace Weather Stripping

Sub-steps:
1. Visually inspect the weather stripping around the rear window for any signs of wear or damage.
2. If damaged, carefully peel off the old weather stripping.
3. Clean the surface to remove any adhesive residue.
4. Cut and apply new weather stripping to the correct length.
5. Press firmly to ensure a proper seal.

4. Repair or Replace Rear Window

Sub-steps:
1. Inspect the rear window for any cracks or gaps that could allow moisture entry.
2. If cracks are found, consider consulting a professional for repair or replacement.
3. For minor damage, use appropriate glass repair resin to seal the crack.

5. Clean Interior Glass

Sub-steps:
1. Use a microfiber cloth and glass cleaner to thoroughly clean the interior of the rear window.
2. Allow the glass to dry completely before testing the HVAC system again.

Tools Required:

Flathead screwdriver
Socket set
Vacuum
Microfiber cloth

Parts Required:

Cabin air filter
Weather stripping (if damaged)
Glass repair resin (if applicable)

Estimated Repair Time: 2-4 hours

Safety Warnings:

Ensure the vehicle is powered off and parked in a safe location before starting any repair work.