How to Replace Rear Window Regulator on a 2017-2021 Mazda CX-5 (Left or Right Door)
Step-by-step rear door panel removal, tools/parts list, safety tips, and window initialization after install
How to Replace Rear Window Regulator on a 2017-2021 Mazda CX-5 (Left or Right Door)
Step-by-step rear door panel removal, tools/parts list, safety tips, and window initialization after install for 2017, 2018, 2019, 2020, 2021
🔧 CX-5 - Rear Window Regulator Replacement
Replacing a rear window regulator on your CX-5 means removing the rear door trim panel, supporting the glass, unbolting the regulator assembly, and swapping it (sometimes with the motor). There are a couple variations (left vs right, regulator-only vs regulator-with-motor), and bolt locations/torque specs can differ.
Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours (one door)
Quick questions (so I give the exact, correct steps + torque specs):
1) Which rear door: left-rear or right-rear?
2) Are you replacing regulator only or regulator + motor (complete assembly)?
⚠️ Safety & Precautions
- ⚠️ Keep fingers clear of the window tracks and scissor/cable mechanism.
- ⚠️ Support the glass before unbolting it; it can drop suddenly.
- ⚠️ Disconnect the battery negative terminal if you’ll unplug the window motor or any door wiring for long periods.
- ⚠️ Do not turn the ignition on with the door airbag connector unplugged (if equipped); it can set an SRS light.
🔧 Required Tools
You'll need the following tools for this repair:
- Trim removal tool set
- Phillips screwdriver #2
- Flat-blade screwdriver (small)
- Ratchet (3/8")
- 10mm socket
- 12mm socket
- Torque wrench (5–60 Nm range)
- Needle-nose pliers
- Painter’s tape (1.5 in)
- Work gloves
- Safety glasses
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Rear window regulator - Qty: 1
- Rear window motor - Qty: 1 (only if not included with regulator)
- Rear door trim panel clips - Qty: 5-10 (as needed)
- Butyl seal tape (door vapor barrier) - Qty: 1 (as needed)
📋 Before You Begin
- Park on level ground and turn the ignition off.
- Lower the window to about halfway if it still moves (this usually lines up the glass clamp bolts).
- If the window is stuck up, be ready to tape the glass to the door frame once the panel is off.
- If you disconnect the battery: use a 10mm socket to remove the negative terminal and isolate it so it can’t spring back.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the rear door trim panel
- Use a trim removal tool set to pry up the window switch panel; unplug the connector.
- Use a Phillips screwdriver #2 to remove any visible screws (commonly behind small covers near the handle/armrest). Use a flat-blade screwdriver (small) to pop the covers first.
- Use a trim removal tool set to pop the panel clips around the perimeter, then lift the panel straight up and off the window ledge.
- Unplug remaining connectors and unhook the door handle cable(s) carefully. Take a photo before unhooking cables.
Step 2: Remove the vapor barrier (water shield)
- Peel the plastic vapor barrier back slowly by hand.
- If the sticky sealant stretches, plan to reseal with butyl seal tape.
Step 3: Support and secure the window glass
- If the glass is movable: reconnect the window switch temporarily and turn ignition on just long enough to position the glass so the clamp bolts are accessible through the door holes, then ignition off.
- Use painter’s tape (1.5 in) to tape the glass to the door frame (run 2–3 strips over the top of the door).
- If the glass is already dropped: lift it by hand to the top and tape it securely.
Step 4: Disconnect the window motor (if removing motor or complete assembly)
- Unplug the motor connector from the regulator/motor using your fingers or needle-nose pliers gently on the tab.
Step 5: Unbolt the glass from the regulator
- Through the access holes, use a 10mm socket to loosen/remove the glass clamp bolts/nuts (design varies by side and build).
- Confirm the glass is fully supported by the tape before the last fastener comes off.
Step 6: Remove the regulator assembly
- Use a 10mm socket and 12mm socket to remove the regulator mounting bolts.
- Carefully snake the regulator out through the large opening in the door.
- If you’re transferring the motor: remove motor fasteners using the correct driver (varies by motor type). Do not rotate the motor gear by hand.
Step 7: Install the new regulator (and motor if needed)
- Feed the new regulator into the door and start all bolts by hand.
- Use a torque wrench (5–60 Nm range) to tighten fasteners to Mazda spec. (I’ll provide exact torque values once you confirm left/right and regulator-only vs regulator+motor.)
- Reconnect the motor electrical connector.
Step 8: Reattach the glass and test operation
- Lower/raise the regulator carriage as needed (brief ignition on) so the glass aligns with the clamps.
- Install the glass clamp bolts/nuts using a 10mm socket, then torque to Mazda spec (I’ll give exact values after your two answers).
- Remove the tape and cycle the window fully up/down while watching that the glass stays level in the run channels.
Step 9: Reassemble the door
- Reinstall the vapor barrier and reseal using butyl seal tape (door vapor barrier) if needed.
- Reconnect all wiring and door handle cable(s).
- Hang the trim panel on the top lip first, then press clips in around the edges.
- Reinstall screws using a Phillips screwdriver #2 and snap trim covers back in place.
✅ After Repair
- Test the window from both the rear switch and the driver master switch.
- If auto-up/down or pinch protection acts weird, perform window initialization: hold the switch to fully down for 2–3 seconds, then fully up and hold 2–3 seconds.
- Check the door for wind noise or water leaks (vapor barrier must seal well).
💰 DIY vs Shop Cost
Shop Cost: $350-$850 (parts + labor)
DIY Cost: $90-$320 (parts only)
You Save: $260-$530 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 hours.
🎯 Ready to get started?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.
Guide for Window Regulator replace for these Mazda vehicles
| Year Make Model | Sub Model | Engine | Body Style |
|---|---|---|---|
| 2021 Mazda CX-5 | - | - | - |
| 2020 Mazda CX-5 | - | - | - |
| 2019 Mazda CX-5 | - | - | - |
| 2018 Mazda CX-5 | - | - | - |
| 2017 Mazda CX-5 | - | - | - |


















