By Justin Your 2008 Hyundai Sonata turn signal is blinking too fast, won’t light up at all, or staying on constantly. You’re wondering what broke, how much it’ll cost, and whether you can fix it yourself in 20 minutes or if you’re looking at a $500 electrical nightmare.
Here’s the reality: 80% of the time, it’s a dead bulb. $6-12, 15 minutes to replace yourself, done. The rest of the time? Loose socket, bad flasher module, or wiring issue—all diagnosable with a single quick test before you spend a dime.
This guide walks you through identifying which problem you have, exactly how to fix it, what it actually costs, and when you should save yourself the headache and call a mechanic.
Why Your Turn Signal Is Hyperflashing (And What It Usually Means)
Your turn signal bulb is at the end of its life. When it burns out, your 2008 Sonata detects the electrical load drop and speeds up the blink as a warning—that’s hyperflashing. In 9 out of 10 cases, it’s a dead bulb. The other 10%? Bad socket, loose ground, or flasher module.
Quick Diagnostic Test
Turn on hazards and walk around. Check both front and rear on the hyperflashing side. If it doesn’t light on hazards, the turn signal bulb is burned out—go to the replacement section. If it lights on hazards but not turn signal, skip to troubleshooting.
Turn Signal Won’t Light At All (Diagnosis Flowchart)
If your turn signal isn’t lighting, here’s how to diagnose what’s wrong.
Turn on hazards. Walk around and check both front and rear on the dead side.
If the light comes on with hazards: Bulb is good, problem is elsewhere (likely loose socket or turn signal switch). Clean socket contacts and see troubleshooting below.
If the light stays off even on hazards: You’ve got a burned-out turn signal bulb. Skip to replacement section.
If Bulb Test Shows Bulb Works
If the bulb lights on hazards but not turn signal, the problem is usually a loose or corroded bulb socket. Open the housing, pull the bulb, and look at the metal socket. If you see white or green corrosion, spray it with electronics cleaner ($5), let it dry, reseat firmly, and test. That fixes it half the time. If still broken, you need professional diagnosis ($50-100) to check the wiring and ground connections.
How to Replace a Burned-Out Turn Signal Bulb (DIY Guide)
This is one of the easiest repairs. No tools except the bulb itself. Time: 15-30 minutes.
What you need: 1156 amber bulb ($6-12), optional electronics cleaner ($5)
Front Signal Bulb Replacement
Turn your steering wheel fully left (driver’s side) or right (passenger’s side) for access.
Step 1: Find the plastic access panel in the wheel well. Remove the single screw.
Step 2: Reach in and locate the bulb socket (plastic cylinder). Twist clockwise about a quarter turn.
Step 3: Pull the old bulb straight out. Use a paper towel—don’t touch the glass.
Step 4: Insert the new bulb. Twist counterclockwise until snug.
Step 5: Test the turn signal. Reattach the panel.
Time: 10-15 minutes. Difficulty: Minimal.
Rear Signal Bulb Replacement
Open the trunk and locate the tail light housing. Remove the 2 screws or clips.
Step 1: Pull the housing out. Locate the bulb socket and rotate counterclockwise.
Step 2: Remove the old bulb. If you see green corrosion on contacts, clean with electronics cleaner.
Step 3: Insert new bulb. Twist clockwise until snug.
Step 4: Test. Reattach housing.
Time: 10-20 minutes. Difficulty: Easy.
Common DIY Mistakes (Avoid These)
Touching bulb glass: Oils shorten lifespan. Use gloves or paper towel.
Loose bulb: Twist firmly into socket. You’ll feel it catch.
Corroded socket: If you see corrosion, clean it. Otherwise the problem repeats in weeks.
One bulb only: Both age together. Replace both while you’re in ($5 extra, saves labor later).
Cost Breakdown: DIY vs. Dealer (Make the Right Choice)
Here’s the honest comparison:
| Option | Total Cost | Time | Skill | Best For |
|---|---|---|---|---|
| DIY Bulb Replace | $6-12 | 15-30 min | None | Simple burned bulb |
| Dealer Bulb Replace | $75-150 | 1-2 hours | N/A | You don’t have 30 minutes |
| DIY Socket Clean | $10-15 | 30 min | Minimal | Corroded contacts |
| Dealer Diagnosis | $50-100 | 1-2 hours | N/A | Problem unclear after tests |
DIY bulb replacement is obviously the financial winner. A $10 bulb vs. a $125 dealer job. But here’s the honest part: only DIY if the problem is clear (hyperflashing = burned bulb) and you’re confident with basic mechanical tasks.
If your diagnostic test didn’t give you a clear answer? Pay $50-100 for a dealer to diagnose. That beats spending $200 guessing on parts that don’t fix anything.
When DIY Makes Sense
Hyperflashing clearly visible (one side dead) → DIY saves you $100+. You know it’s the bulb, it’s a 15-minute job, the risk of something going wrong is near zero. Replace the bulb yourself.
When Dealer (or Mobile Mechanic) Makes Sense
Problem is unclear after hazard testing. You don’t know if it’s the bulb, socket, or wiring. Pay a pro $50-100 to figure it out. Then you can decide if the fix is DIY-able.
You suspect wiring or electrical issues. That requires a multimeter, wiring diagrams, and electrical knowledge. Not worth the risk of misdiagnosing. $100-200 pro diagnosis saves thousands in wrong parts.
You don’t have time. Dealer gets it done in an hour while you work. Sometimes time is worth the money.
Warranty matters to you. Dealer repairs come with warranty coverage. DIY doesn’t. If you’re wrong and break something, that’s on you.
What If Replacing the Bulb Didn’t Fix It? (Troubleshooting Next Steps)
You replaced the turn signal bulb and it still hyperflashes or won’t light. What now?
First, make sure the bulb is fully seated (twisted firmly into the socket). Loose bulb = intermittent light = looks broken when it’s just loose. Remove it, clean the socket contacts with electronics cleaner, and reseat it firmly. Test again.
If that didn’t work, the problem is likely the bulb socket itself (corrosion has spread inside), the turn signal flasher module (relay that controls the blink rate), or a wiring/ground issue.
Socket Inspection & Contact Cleaning
Pull the bulb out again. Look inside the socket for corrosion. If you see it, use a small piece of fine sandpaper or a pencil eraser to gently clean the metal contacts. Compressed air helps blow out debris. Reseat the bulb and test.
If the socket is clean but still failing, the problem is deeper—likely the flasher module or a ground connection. Time to call a pro. A mechanic can diagnose this in 20 minutes with a multimeter.
When to Call a Professional (Flasher or Wiring Issues)
If you’ve replaced the bulb, cleaned the socket, and it’s still broken—the problem is now a $150-250 territory (flasher module replacement) or a $200-400+ territory (wiring/ground repair). These aren’t DIY jobs unless you’re comfortable working with electrical systems.
Cost: Flasher replacement $100-200, wiring repair $150-400+ depending on what’s wrong. Mobile mechanic (comes to you) typically costs 20-30% less than a dealership.
The key insight: Stop troubleshooting after the bulb replacement. If that didn’t fix it, professional diagnosis is cheaper than guessing.
PEOPLE ALSO ASK
Can I drive with a broken turn signal?
No—it’s illegal and unsafe. Fix it same-day if possible.
How much does a turn signal bulb cost at the dealer?
Bulb $10-15 + labor $65-100 = $75-150 total. DIY: $6-12.
Why did my turn signal work, then suddenly stop?
Bulb reached end of life. Test with hazards to confirm the bulb is burned.
What if I replace the bulb and it still doesn’t work?
Socket is likely corroded (clean contacts) or it’s a flasher/wiring issue (call a pro).
Do both sides fail at the same time?
Usually no, but they age together. Replace both to avoid labor costs later.
Can I use LED bulbs?
Yes, but some LEDs cause hyperflashing. Buy ones marketed for Sonatas or stick with standard amber.
When should I call a mechanic instead of DIY?
If the bulb replacement didn’t fix it or if you’re unsure about diagnosis. Professional diagnosis ($50-100) beats guessing on parts.