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Both headlights not working at the same time 1999 Toyota Paseo

By ClearTheCode · Published 2026-05-19 · ~9 min read

If both headlights not working at the same time on your 1999 Toyota Paseo, learn common causes like fuses or relays and how to diagnose the issue.

At a glance

Difficulty
6/10 — Moderate
Est. repair cost
$100 – $900 (parts + typical shop labor)
OEM tooling
Standard OBD-II scanner and hand tools
Common symptoms
  • No low beam headlights when the switch is turned on.
  • No high beam headlights when activated.
  • Parking lights
  • taillights
  • and dashboard lights may still function normally
  • indicating the problem is specific to the

Experiencing both headlights not working at the same time on your 1999 Toyota Paseo can be a significant safety concern, especially when driving at night. This common electrical problem, where neither the driver's nor passenger's headlight illuminates, often points to a shared component failure rather than individual bulb issues. Understanding the potential causes and how to diagnose them can help you restore proper lighting and ensure safe driving.

What drivers notice on this 1999 Toyota Paseo

The most obvious sign is a complete lack of illumination from the front of the vehicle when the headlight switch is engaged. This isn't just one dim bulb; it's a total absence of light from both the driver's and passenger's side headlights. This can be particularly alarming if it happens suddenly while driving, making it impossible to see the road ahead or for other drivers to see your vehicle.

At a glance: difficulty, repair cost, and diagnostic workflow

  • Difficulty Rating: 6/10 — Moderate
  • Common Symptoms: No low beam headlights when the switch is turned on.; No high beam headlights when activated.; Parking lights, taillights, and dashboard lights may still function normally, indicating the problem is specific to the ; Sometimes, a burning smell might be present if a fuse has blown due to an electrical short, though this is less common f
  • Estimated Repair Cost: $100–$900 (parts + typical shop labor)
  • OEM Tooling Required: Standard OBD-II scanner and hand tools

Diagnostic workflow:

  1. Confirm the symptom on your vehicle.
  2. Scan for stored or pending codes with an OBD-II tool.
  3. Inspect the most common causes in this guide (visual checks first).
  4. Run verification tests before replacing parts.
  5. Repair, clear codes, and verify on a test drive.

Symptoms and warning signs

When both headlights fail simultaneously, drivers typically observe:

  • No low beam headlights when the switch is turned on.
  • No high beam headlights when activated.
  • Parking lights, taillights, and dashboard lights may still function normally, indicating the problem is specific to the headlight circuit.
  • Sometimes, a burning smell might be present if a fuse has blown due to an electrical short, though this is less common for a simple fuse failure.

How to verify and confirm the issue

To confirm that both headlights are indeed not working and to begin narrowing down the cause, perform these checks:

  • Check the headlight switch: Ensure the headlight switch is fully engaged for both low and high beams. Sometimes, a loose or faulty switch can prevent power from reaching the headlights.
  • Inspect the bulbs: While unlikely for both to fail simultaneously, visually inspect both headlight bulbs. Look for broken filaments or discoloration within the glass. If one looks obviously bad, replace it and retest.
  • Check fuses: Locate your vehicle's fuse box (typically under the hood or inside the cabin, near the dashboard). Consult your owner's manual for the exact location and identification of the headlight fuses. There might be separate fuses for left and right headlights, or a single main fuse for the headlight circuit. A blown fuse will have a visibly broken wire inside.
  • Test the headlight relay: Many vehicles use a relay to power the headlights. The relay is usually in the fuse box. You can often test a relay by swapping it with another identical, known-good relay from a non-critical circuit (e.g., horn relay) to see if the headlights then work.
  • Listen for a click: When you turn on the headlights, listen for a faint click from the fuse box area, which could indicate the relay is attempting to engage.

Common causes (most likely first)

When both headlights fail at once, the problem usually lies in a component that powers both lights. Here are the most common causes:

  • Blown Headlight Fuse: This is the most frequent culprit. A single fuse often protects the entire headlight circuit or a main fuse protects both low beams, causing both to fail if it blows.
  • Faulty Headlight Relay: The headlight relay switches power to the headlights. If it fails, power won't reach either bulb. Relays can wear out or become internally damaged.
  • Defective Headlight Switch: The switch on your dashboard or steering column controls the headlight circuit. If it's faulty, it won't send the signal or power to activate the headlights.
  • Wiring Issues or Bad Ground: Corrosion, a loose connection, or a damaged ground wire in the main headlight circuit can prevent power from reaching both headlights. A common ground point for both headlights can fail.
  • Both Bulbs Failed Simultaneously: While less common, it's possible, especially if both bulbs are old and nearing the end of their lifespan.

Step-by-step diagnosis and fixes

Follow these steps to diagnose and potentially fix the issue:

  • Step 1: Check Fuses First: Always start here. Locate the headlight fuse(s) in your owner's manual. Pull them out and visually inspect the filament. If blown, replace with a fuse of the exact same amperage. If it blows again immediately, you have a short circuit that needs further investigation.
  • Step 2: Test the Headlight Relay: Identify the headlight relay using your owner's manual. You can try swapping it with a known good, identical relay from another non-essential circuit (like the horn or fog lights) to see if the headlights come on. If they do, replace the relay.
  • Step 3: Inspect the Headlight Switch: With the battery disconnected, remove the headlight switch (refer to your service manual for specific instructions). Check for loose wires or burnt contacts. If you have a multimeter, you can test for continuity across the switch terminals in different positions. A faulty switch will need replacement.
  • Step 4: Check for Power at the Headlight Connectors: With the headlight switch on, use a multimeter or test light to check for voltage at the electrical connector for each headlight bulb. If there's no power, the issue is upstream (fuse, relay, switch, or wiring). If there is power, but the bulb doesn't light, the bulb itself or its ground connection is likely the problem.
  • Step 5: Inspect Wiring and Ground Points: Trace the wiring from the headlight connectors back towards the fuse box and switch, looking for any signs of damage, fraying, or corrosion. Pay close attention to ground wires, which are typically black. A loose or corroded ground connection can prevent the circuit from completing.

Repair options and cost factors

Repairing both headlights not working at the same time on your 1999 Toyota Paseo typically involves replacing the faulty component. The cost factors depend on the part and whether you do it yourself or hire a professional.

  • Fuse Replacement: Very inexpensive, usually just a few dollars for a pack of fuses. DIY friendly.
  • Relay Replacement: Relays are generally affordable, ranging from $10-$40. Easy to replace for most DIYers.
  • Headlight Switch Replacement: The switch itself can cost anywhere from $50-$150 or more, depending on the specific part. Installation can be more involved, potentially requiring dashboard panel removal.
  • Wiring Repair: Costs vary widely depending on the extent of the damage. Simple repairs might involve splicing wires, while extensive damage could require replacing entire sections of the harness, which can be costly in parts and labor.
  • Bulb Replacement: If by chance both bulbs failed, they are relatively inexpensive, typically $10-$30 per bulb.

For more detailed repair guides, you can explore All repair guides on our site.

When to see a professional

While many of these diagnostic steps are DIY-friendly, there are times when it's best to consult a professional technician:

  • Persistent Blown Fuses: If you replace a fuse and it blows again immediately, it indicates a short circuit that needs expert diagnosis to prevent further electrical damage.
  • Complex Electrical Diagnosis: If you've checked the fuses, relay, and switch, and still can't pinpoint the problem, a professional has specialized tools and expertise to trace electrical faults.
  • Wiring Damage: Extensive or hard-to-reach wiring damage is best left to technicians who can safely and effectively repair or replace harnesses.
  • Lack of Tools or Experience: If you don't have the necessary tools (like a multimeter) or feel uncomfortable working with your vehicle's electrical system, a professional can ensure the job is done correctly and safely.

Frequently asked questions

Why would both headlights stop working at once?

Both headlights typically stop working simultaneously because they share a common power source or control component. The most common reasons are a blown main headlight fuse, a faulty headlight relay, or a defective headlight switch that controls the entire circuit for both lights.

Can I drive my 1999 Toyota Paseo without headlights?

No, it is illegal and extremely unsafe to drive your 1999 Toyota Paseo without functional headlights, especially at night or in low-visibility conditions. Headlights are crucial for illuminating the road ahead and making your vehicle visible to other drivers, preventing accidents.

Are headlight issues common on older Toyota Paseos?

Like many older vehicles, the 1999 Toyota Paseo can experience headlight issues as electrical components age and wear out. Fuses can blow, relays can fail, and wiring can corrode over time, making these types of electrical problems relatively common as the vehicle accumulates mileage and years.

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Sources and further reading

This information is not a substitute for OEM service procedures and should not be used for safety-critical work without consulting a qualified technician.

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