🔧 Ascent - Rear Turn Signal Bulb Replacement

Easy job. You’ll remove the complete rear combination lamp, change its amber wedge bulb, and reinstall the lamp. Subaru specifies a 12V 21W WY21W amber bulb, commonly sold as a 7440A or 7440NA. subaru.oemdtc.com

Difficulty Level: Beginner | Estimated Time: 20-30 minutes for both sides

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⚠️ Safety & Precautions

• 🛑 Switch the ignition and all exterior lights off.
• 🌡️ Let the lamp cool before touching the bulb or socket.
• 🧤 Wear clean gloves and avoid touching the bulb glass with bare fingers.
• 🔌 Battery disconnection isn’t required for this repair.
• ⚠️ Pull the lamp straight rearward. Twisting it sideways can damage its plastic guide pins.

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🔧 Required Tools

You'll need the following tools for this repair:

• Phillips #2 screwdriver
• Plastic trim removal tool
• Nitrile gloves
• Safety glasses
• Clean microfiber cloth

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• WY21W amber rear turn signal bulb, 12V 21W - Qty: 2

Replace both sides together if the bulbs are the same age. A 7440A or 7440NA amber incandescent bulb matches the specified 21-watt wedge format. Plain incandescent is the cleanest choice here because it won’t introduce LED fast-flash problems.

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📋 Before You Begin

• 🚙 Park your Ascent on level ground and select Park.
• 🔑 Turn the ignition off and keep the key away from the vehicle.
• 💡 Confirm the failed side by briefly operating the hazard lights, then switch them off.
• 🚪 Open the rear gate completely.
• 📦 Place a clean microfiber cloth nearby so the lamp can’t scratch the paint.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the screw covers

• Locate the two small covers along the inside edge of the rear combination lamp.
• Use a plastic trim removal tool to lift the covers carefully.
• Set the covers somewhere safe.

Step 2: Remove the lamp screws

• Use a Phillips #2 screwdriver to remove the upper and lower retaining screws.
• Support the lamp with your free hand as the second screw comes out.
• Keep both screws with their covers.

Step 3: Release the rear combination lamp

• Grip the lamp firmly and slide it straight toward the rear of your Ascent.
• If it feels stuck, use the plastic trim removal tool only at the lamp’s inside edge while maintaining rearward pressure.
• Do not pry outward or rotate the assembly. Subaru uses guide pins, a catch, and a retaining clip behind the lamp. subaru.oemdtc.com

Step 4: Disconnect the lamp connector

• Support the lamp on the clean microfiber cloth.
• Press the electrical connector’s locking tab with your fingers and pull the connector straight out.
• Pull on the connector body, not its wires.

Step 5: Remove the turn signal socket

• Identify the rear turn signal socket. Subaru’s diagram places it below the backup and rear side-marker sockets.
• Grip the socket and rotate it counterclockwise approximately one-quarter turn.
• Pull the socket straight out of the lamp housing. subaru.oemdtc.com

Step 6: Replace the bulb

• Wear nitrile gloves and pull the old wedge bulb straight out of its socket.
• Push the new WY21W amber 12V 21W bulb straight into the socket until fully seated.
• If you accidentally touch the glass, clean it with the microfiber cloth before installation.

Step 7: Test the new bulb

• Reconnect the electrical connector temporarily.
• Switch on the hazard lights and verify that the new bulb flashes at the normal speed.
• Switch the hazard lights off before continuing.
• If it doesn’t light, switch everything off and reseat the bulb and connector.

Step 8: Reinstall the bulb socket

• Insert the socket into the lamp housing in its keyed position.
• Rotate it clockwise by hand until it locks.
• Make sure the socket seal sits evenly against the housing to help keep moisture out.

Step 9: Reinstall the lamp assembly

• Reconnect the electrical connector until its locking tab clicks.
• Align the lamp’s guide pins, catch, and clip with their openings in the body.
• Push the lamp straight forward until it sits flush with the body. Subaru specifically calls for aligning these mounting points before seating the lamp. subaru.oemdtc.com
• Don’t force it. If the lamp won’t sit flush, remove it and realign the pins.

Step 10: Secure the lamp

• Start both screws by hand to prevent cross-threading.
• Use the Phillips #2 screwdriver to tighten them evenly until snug.
• No bulb-service screw torque is published in the owner procedure. Don’t overtighten the screws against the plastic lamp housing.
• Press both screw covers back into place.

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✅ After Repair

• ✅ Operate the left signal, right signal, and hazard lights.
• 👀 Verify that both rear signals flash evenly and at normal speed.
• 🔍 Check that the lamp sits flush and doesn’t move when pressed lightly.
• 💧 After the next wash or rain, inspect the lamp briefly for internal condensation.

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💰 DIY vs Shop Cost

Shop Cost: $45-$100 per side

DIY Cost: $4-$15 for a pair of incandescent bulbs

You Save: $35-$90 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.2-0.4 hour.

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🎯 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.