Safety Warning
- Ensure all electrical connections are properly insulated and weatherproofed
- Test all tail light functions before driving to ensure legal compliance
- Use proper gauge wire for the current draw of the new lights to prevent overheating
Quick Diagnosis Summary
Converting your 1987 Ford Ranger to semi-style tail lights can give your truck a distinctive, modern appearance. However, this upgrade requires proper wiring conversion due to fundamental differences between your Ranger's original electrical system and semi-style lighting configurations. Understanding the conversion process will help you achieve a professional installation while maintaining proper function and legal compliance.
Understanding the Wiring Difference
Your 1987 Ford Ranger uses a 2-wire tail light system where a single bulb handles both brake lights and turn signals at different brightness levels. Semi-style lights, commonly found on commercial trucks, use a 3-wire system with separate bulbs for brake lights and turn signals. This fundamental difference requires a converter to translate between the two systems.
Symptoms Indicating Conversion Issues
When attempting to install semi-style lights without proper conversion, you may experience several telltale signs:
- Non-functioning turn signals: Turn signals may not work at all or only illuminate as brake lights
- Brake lights staying on: Brake lights may remain illuminated constantly or not function properly
- Rapid turn signal flashing: The turn signal may flash much faster than normal, indicating a load mismatch
- Dim or erratic lighting: Lights may appear dimmer than expected or flicker inconsistently
- Blown fuses: Incorrect wiring may cause electrical shorts leading to blown fuses
Common Causes of Conversion Problems
Improper 3-to-2 Wire Converter Placement
The most critical component in this conversion is the 3-to-2 wire converter module. This device must be properly installed between your Ranger's existing wiring harness and the new semi-style lights. Many installation problems occur when:
- The converter is installed in an incorrect location, such as under the hood instead of near the rear lights
- Wrong converter type is used for the specific light configuration
- Connections are made incorrectly, mixing up brake and turn signal wires
- The converter lacks proper grounding, causing erratic operation
Flasher Unit Compatibility Issues
Your 1987 Ford Ranger's original flasher unit was designed for incandescent bulbs with specific current draw characteristics. Semi-style lights, especially LED versions, may have different electrical requirements that cause:
- Hyperflashing (rapid blinking) due to lower current draw
- Complete failure to flash with LED lights
- Inconsistent timing between left and right turn signals
Wire Gauge Inadequacy
While less common, some semi-style light configurations may draw more current than your Ranger's original tail lights. This can result in:
- Voltage drop causing dim lights
- Wire overheating, especially in hot weather
- Premature failure of connections and components
Proper Diagnosis Steps
To identify the specific cause of your conversion issues, follow these diagnostic steps:
Step 1: Verify Converter Installation
Check that your 3-to-2 wire converter is installed in the correct location, typically near the rear of the vehicle. Verify all connections match the wiring diagram provided with the converter.
Step 2: Test Light Functions
With the engine running, test each light function separately:
- Left turn signal
- Right turn signal
- Brake lights
- Running lights
- Hazard lights
Step 3: Check Voltage Readings
Use a multimeter to verify proper voltage at the converter input and output. You should see 12 volts at all connection points when the respective functions are activated.
Step 4: Inspect Flasher Unit
Locate your flasher unit (usually in the fuse box) and check if it's compatible with your new light configuration. The part number should indicate load capacity.
Repair Options and Solutions
Professional Installation
Having a qualified automotive electrician perform the conversion ensures:
- Proper converter selection and placement
- Correct wire routing and protection
- Compliance with local vehicle lighting regulations
- Warranty coverage for the installation work
DIY Installation Considerations
If you choose to perform the conversion yourself, ensure you have:
- Basic electrical knowledge and tools
- Proper 3-to-2 wire converter for your specific application
- Electrical tape, heat shrink tubing, and weatherproof connectors
- Multimeter for testing connections
- Vehicle-specific wiring diagrams
Cost Breakdown
The total cost for a tail light wiring conversion typically ranges from $15 to $50, depending on the components needed:
Parts Costs:
- 3-to-2 wire converter: $8-$25
- Electronic flasher unit: $5-$15
- Additional wiring/connectors: $2-$10
Labor Costs (if professional installation):
- Shop labor: $50-$100 per hour
- Installation time: 1-2 hours typically
Prevention and Maintenance Tips
To ensure long-lasting performance of your converted tail light system:
- Use quality components: Invest in reputable brand converters and flasher units
- Protect connections: Use dielectric grease and proper weatherproofing on all connections
- Regular inspection: Check all light functions monthly, especially before long trips
- Keep spare bulbs: Carry replacement bulbs appropriate for your semi-style lights
- Monitor for corrosion: Inspect wiring connections annually for signs of corrosion or damage
Safety and Legal Considerations
Before driving with your converted tail lights, ensure all functions work properly and comply with local regulations. Most jurisdictions require:
- Functioning brake lights that illuminate when brakes are applied
- Turn signals that flash at the proper rate
- Running lights that illuminate with headlights
- Proper light colors (red for brake/turn, amber for turn signals in some areas)
Frequently Asked Questions
No, you cannot install semi-style lights without a proper 3-to-2 wire converter. The Ranger uses a 2-wire system while semi-style lights require a 3-wire system. Without a converter, the lights will not function correctly and may cause electrical problems.
Rapid flashing (hyperflashing) typically occurs when LED semi-style lights are installed without upgrading the flasher unit. LED lights draw less current than incandescent bulbs, causing the original flasher to think a bulb is burned out. Install an electronic flasher unit to resolve this issue.
The converter should be installed near the rear of the vehicle, typically behind the cab or in the bed area, between the existing vehicle harness and the new lights. This location provides easy access for connections while keeping the converter away from engine heat and road debris.
Test all light functions individually: brake lights should illuminate when brakes are pressed, turn signals should flash at normal speed, and running lights should come on with headlights. Use a multimeter to verify 12 volts at both input and output connections when functions are activated.
Not all converters are the same. Choose a converter rated for your specific current load and designed for automotive use. Some converters are designed for trailers and may not work properly with vehicle lighting systems. Check the manufacturer's compatibility information.
Legality varies by jurisdiction, but generally, as long as the converted lights meet brightness, color, and positioning requirements, they should be legal. Ensure all functions work properly and consider checking with local authorities if you have concerns about compliance.