1998-2000 Volvo S70 Tail Light: Solving Circuit Board Failures and Fitment Issues
This guide covers the common causes of tail light problems in the 1998-2000 Volvo S70, from melted circuit boards to critical sedan-only compatibility.
- The most common failure is the circuit board/bulb holder, which overheats and melts due to corrosion. Always inspect this on a used part.
- These tail lights fit the 1998-2000 S70 Sedan ONLY and are not interchangeable with V70 wagons or C70 coupes.
- Replacement is extremely easy, requiring only an 8mm socket and about 20 minutes, making it an ideal DIY repair.
- A good used OEM assembly is often a better and more durable choice than a new aftermarket part, which may use inferior plastic.
Symptoms of Tail Light Failure
Diagnosing a faulty tail light on a Volvo S70 often involves more than just checking a bulb. Due to the design of the bulb holder circuits, specific electrical symptoms are common.
- "BULB FAILURE" Message on Dash: This is the most common indicator. The car's monitoring system detects incorrect resistance in a circuit, which can be caused by a burnt-out bulb, a poor connection, or a failing circuit board trace.
- Dim or Flickering Lights: A light that appears dimmer than the one on the opposite side or flickers intermittently often points to a bad ground connection or corrosion on the bulb socket or circuit board. This creates high resistance, which generates heat and can lead to further damage.
- Brake Lights or Running Lights Not Working: You may find that the brake light works but the running light doesn't (or vice-versa), even though they use the same dual-filament bulb. This often points to a failure in a specific trace on the circuit board rather than the bulb itself.
- Bulbs Burn Out Repeatedly: If you are replacing the same bulb frequently, it could be caused by excessive heat from a high-resistance connection melting the socket or by voltage spikes from a failing electrical system component.
- Visible Damage or Moisture: Cracks in the lens or housing can allow water inside, which will quickly corrode the bulb sockets and the circuit board, leading to electrical failures. You may see condensation or water sloshing inside the lens.
- Melted Plastic: In many cases, a poor connection generates enough heat to melt the plastic on the bulb holder or the main housing, especially around the brake light bulb contact.
Known Issues, Recalls, and TSBs
While there are no recalls specifically for the tail light assemblies on the 1998-2000 S70, several related issues are important for owners to know.
Common Failure: Tail Light Circuit Board
The most frequent problem with these tail lights is the failure of the bulb holder, which contains the printed circuit traces. Over time, the contact points between the bulb socket and the copper traces on the board corrode. This corrosion creates resistance, which generates heat. The heat can melt the plastic around the contacts, leading to a loose connection and eventual failure of the light. This issue is especially common with aftermarket tail light assemblies, which may use lower-quality plastic that is less resistant to heat.
Warning: A related and critical safety recall for these vehicles is NHTSA Campaign #04V504000 (Volvo Recall #142). This recall addresses a faulty master headlight switch that can cause intermittent or complete failure of the headlights, dramatically increasing the risk of a crash. While it doesn't directly affect the tail lights, it points to the sensitivity of the car's lighting electronics. Ensure this recall has been performed on the vehicle.
Buying a Used S70 Tail Light: What to Inspect
A used OEM tail light is often a better choice than a cheap aftermarket replacement due to superior materials and fit. However, careful inspection is key to avoiding a part with the same common failures.
Compatibility Check: The single most important check is vehicle model. These tail lights fit 1998-2000 Volvo S70 SEDAN models ONLY. They will not fit the V70 (wagon) or C70 (coupe/convertible), which use completely different light assemblies.
Inspection Checklist:
- Separate the Bulb Holder: Ask the seller to twist and remove the gray or black bulb holder panel from the back of the red lens housing. This is essential for proper inspection.
- Inspect for Melting (The #1 Priority): Look closely at the plastic bulb sockets on the holder panel. Pay special attention to the brake light socket. Check for any signs of browning, distortion, or melted plastic around the metal contacts. If you see any melting, the part is already failing and should be rejected.
- Check Circuit Board Traces: Examine the thin copper lines on the circuit board. Look for any green or white corrosion, black burn marks, or areas where the trace has lifted or peeled away from the board.
- Examine the Lens and Housing: Check the red/clear lens for cracks, deep scratches, or hazing. Look for any signs of moisture or a waterline inside the housing, which indicates a bad seal.
- Verify Mounting Studs: Ensure all four threaded mounting studs on the back of the housing are intact and not cracked or broken off.
Pro Tip: When you find a good used unit, apply a small amount of dielectric grease to the bulb contacts and the connection points on the circuit board. This helps prevent moisture intrusion and corrosion, prolonging the life of the assembly.
Cost of 1998-2000 Volvo S70 Tail Lights
| Part Type | Estimated Cost |
|---|---|
| New OEM | $150 - $250+ (often sold in components) |
| New Aftermarket | Not commonly available |
| Used OEM | $40 - $110 |
| Shop Labor to Install | $50 - $100 |
Replacement Guide
Replacing the tail light assembly on an S70 is a very simple DIY task that requires minimal tools and time.
- Difficulty: 1/5 (Very Easy)
- Time: 15-20 minutes per side
- Tools Needed: 8mm socket with a small extension and ratchet.
Step-by-Step Instructions:
- Open the trunk.
- Pull back the carpeted liner behind the tail light. There is usually a small access door or panel to remove.
- You will see four 8mm nuts holding the tail light assembly to the body.
- Before removing the nuts, disconnect the main electrical connector going to the bulb holder.
- Carefully remove the four 8mm nuts. Be careful not to drop them down into the body panels.
- From the outside of the car, gently pull the tail light assembly straight back and out of the vehicle.
- If your replacement assembly did not come with a bulb holder, twist your old one to remove it and install it in the new housing.
- Installation is the reverse of removal. Guide the new assembly into place, hand-tighten the four nuts, reconnect the electrical plug, and then snug the nuts down. Do not overtighten, as you can crack the plastic housing.
Technical Specifications & Part Numbers
The S70 uses four separate tail light assemblies. It is critical to order the correct part for the specific location and side needed. Part numbers can supersede, but the ones below are commonly found on used original parts.
| Location | Common OEM Part Numbers |
|---|---|
| Outer Left (Driver Side) | 9151629 |
| Outer Right (Passenger Side) | 9151630, 9157007 |
| Inner Left (Driver, Trunk-Mounted) | 9151633, 9151635, 9157008 |
| Inner Right (Passenger, Trunk-Mounted) | 9151634, 9151636, 9157009 |
| Bulb Holder / Socket | 9151640, 9151642 |
Frequently Asked Questions (FAQ)
Why does my dashboard say "BULB FAILURE" when the light still works?
This is a classic symptom of a failing circuit board or corroded socket. The car's monitoring system detects a change in electrical resistance even if the bulb hasn't completely burned out. This high resistance is what leads to the overheating and melting issues.
Can I just replace the circuit board or bulb holder?
Yes, the bulb holder (which contains the circuit board) can be purchased and replaced separately. They are often available used for around $10-$20. However, if the old holder melted, inspect the main tail light housing for heat damage where the holder makes contact.
Will a tail light from a Volvo V70 or C70 fit my S70?
No. The S70 is a sedan and has a unique four-piece tail light setup. The V70 is a wagon and the C70 is a coupe/convertible; both have completely different body shapes and tail light designs. You must use a tail light from a 1998-2000 S70.
How can I fix a melted bulb socket?
For minor corrosion, you can try cleaning the metal contacts with a small wire brush or sandpaper and bending the tabs for a tighter fit. However, once the plastic has melted, the best and safest solution is to replace the bulb holder assembly. For advanced DIYers, some owners bypass the faulty circuit board entirely by soldering wires directly to the bulb sockets, but this is a more involved repair.
Technical Specifications
OEM Part Numbers: Outer Left: 9151629 Outer Right: 9151630, 9157007 Inner Left: 9151633, 9151635, 9157008 Inner Right: 9151634, 9151636, 9157009
Vehicle uses a four-piece tail light system (two outer on body, two inner on trunk lid). Assemblies are secured with four 8mm nuts.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Volvo S70:
- 🛍️ Shop This Part
- Symptoms of Tail Light Failure
- Known Issues, Recalls, and TSBs
- Common Failure: Tail Light Circuit Board
- Buying a Used S70 Tail Light: What to Inspect
- Inspection Checklist:
- Cost of 1998-2000 Volvo S70 Tail Lights
- Replacement Guide
- Step-by-Step Instructions:
- Technical Specifications & Part Numbers
- Frequently Asked Questions (FAQ)
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