If you own a 99 Ford F350 and are planning to haul a trailer, you may need to install a trailer wiring harness to ensure that all of the lights and signals on your trailer work properly. In this article, we will provide you with a comprehensive guide on 99 Ford F350 trailer wiring diagrams, including wiring diagram diagrams for different types of trailer connections, frequently asked questions, and tips for troubleshooting common wiring problems.
Trailer Wiring Diagrams
The first step in installing a trailer wiring harness on your 99 Ford F350 is to determine which type of connection your trailer requires. There are several types of trailer connections, including four-pin, five-pin, six-pin, and seven-pin connections. Each of these connections requires a different type of wiring diagram, so it is important to choose the correct one for your trailer.
Four-Pin Trailer Connection Wiring Diagram
If your trailer has a four-pin connection, you will need to use the following wiring diagram:
| Wire Color | Function |
|---|---|
| Brown | Running Lights |
| Yellow | Left Turn Signal |
| Green | Right Turn Signal |
| White | Ground |
The brown wire should be connected to the running lights on your trailer, the yellow wire should be connected to the left turn signal, the green wire should be connected to the right turn signal, and the white wire should be connected to the ground.
It is important to note that some trailers may have a fifth wire for the brake light circuit. If your trailer has this wire, it should be connected to the blue wire on your wiring harness.
Five-Pin Trailer Connection Wiring Diagram
If your trailer has a five-pin connection, you will need to use the following wiring diagram:
| Wire Color | Function |
|---|---|
| Brown | Running Lights |
| Yellow | Left Turn Signal |
| Green | Right Turn Signal |
| White | Ground |
| Blue | Electric Brake |
The brown wire should be connected to the running lights on your trailer, the yellow wire should be connected to the left turn signal, the green wire should be connected to the right turn signal, the white wire should be connected to the ground, and the blue wire should be connected to the electric brake.
Six-Pin Trailer Connection Wiring Diagram
If your trailer has a six-pin connection, you will need to use the following wiring diagram:
| Wire Color | Function |
|---|---|
| Black | Battery Charge |
| Brown | Running Lights |
| Yellow | Left Turn Signal |
| Green | Right Turn Signal |
| White | Ground |
| Blue | Electric Brake |
The black wire should be connected to the battery charge, the brown wire should be connected to the running lights on your trailer, the yellow wire should be connected to the left turn signal, the green wire should be connected to the right turn signal, the white wire should be connected to the ground, and the blue wire should be connected to the electric brake.
Seven-Pin Trailer Connection Wiring Diagram
If your trailer has a seven-pin connection, you will need to use the following wiring diagram:
| Wire Color | Function |
|---|---|
| Black | Battery Charge |
| Brown | Running Lights |
| Yellow | Left Turn Signal |
| Green | Right Turn Signal |
| White | Ground |
| Blue | Electric Brake |
| Red | Reverse Lights |
The black wire should be connected to the battery charge, the brown wire should be connected to the running lights on your trailer, the yellow wire should be connected to the left turn signal, the green wire should be connected to the right turn signal, the white wire should be connected to the ground, the blue wire should be connected to the electric brake, and the red wire should be connected to the reverse lights.
Frequently Asked Questions
What if my trailer has different colored wires?
If your trailer has different colored wires than those listed in the wiring diagrams above, you will need to use a voltage tester to determine which wire is for each function. Once you have identified the correct wires, you can connect them according to the corresponding function in the wiring diagram.
What if my trailer has a six-pin connector, but my F350 has a seven-pin connector?
If your trailer has a six-pin connector and your F350 has a seven-pin connector, you will need to purchase a wiring adapter to make the connection. The wiring adapter typically has a six-pin connector on one end and a seven-pin connector on the other end, allowing you to connect your trailer to your F350.
What if my lights or signals on my trailer are not working?
If the lights or signals on your trailer are not working, there are several possible causes. First, check to make sure that the wiring is connected properly and that there are no loose or damaged wires. Next, check the fuses in your F350’s fuse box to make sure they are not blown. If the fuses are okay, you may need to replace the bulbs in your trailer’s lights. If none of these solutions work, you may need to take your trailer to a professional mechanic or electrician to be repaired.
Troubleshooting Tips
No Power
If you are not getting power to your trailer’s lights or signals, check the wiring connections and fuses as described above. If these solutions do not work, use a voltage tester to check for power at the wiring harness. If there is still no power, you may have a faulty wiring harness or a problem with your F350’s electrical system.
Intermittent Power
If your trailer’s lights or signals work intermittently, check the wiring connections for loose or damaged wires. Also, check the bulbs in your trailer’s lights to make sure they are not loose or damaged. If these solutions do not work, you may have a problem with your trailer’s electrical system.
Overloading Circuit
If you are overloading the circuit on your F350’s electrical system, you may experience problems with your trailer’s lights or signals. Make sure that you are not exceeding the maximum towing capacity of your F350 and that you are not overloading the circuit by using too many electrical devices at once. If these solutions do not work, you may need to upgrade your F350’s electrical system or install a higher-capacity wiring harness.
Conclusion
Installing a trailer wiring harness on your 99 Ford F350 can be a straightforward process if you have the correct wiring diagram and follow the instructions carefully. By using the information provided in this article, you should be able to install your trailer wiring harness quickly and easily, allowing you to tow your trailer with confidence.
