Your trailer breakaway system is one of the most important safety features on a trailer with electric brakes. If the trailer ever becomes disconnected from the tow vehicle, the breakaway system activates the trailer brakes to help stop the trailer and reduce the risk of a runaway accident.
Over time, breakaway switches, batteries, wiring, and chargers can fail due to weather, corrosion, age, or damage. Replacing a faulty breakaway system helps keep your trailer legal, safe, and road-ready.
Here’s a step-by-step guide to replacing a trailer breakaway system.
Signs Your Breakaway System May Need Replacing
You may have a bad breakaway system if you notice:
- Dead or weak breakaway battery
- Damaged or missing pull pin
- Broken switch housing
- Corroded wiring
- Trailer brakes not activating during testing
- Cracked battery box
- Warning lights not functioning (if equipped)
If the system doesn’t activate the trailer brakes properly, replacement may be necessary.
Parts You May Need
Depending on the issue, you may replace:
- Breakaway switch
- Breakaway battery
- Battery box
- Charger/maintainer
- Wiring harness
- Complete breakaway kit
Many trailer owners choose to install a complete kit to simplify repairs.
Tools & Supplies Needed
Before starting, gather:
- Wire cutters/strippers
- Crimpers
- Heat shrink connectors or butt connectors
- Electrical tape
- Drill/socket set (if mounting hardware changes)
- Multimeter or test light
- Zip ties
- Replacement breakaway system
Step 1: Disconnect Power
Before beginning:
- Disconnect the trailer from the tow vehicle
- Disconnect trailer battery power (if equipped)
This helps prevent accidental shorts.
Step 2: Remove the Old Breakaway Switch
The breakaway switch is usually mounted near the trailer tongue.
Remove:
- Mounting screws or bolts
- Wiring connections
Most switches use two wires:
- Brake power wire
- Battery power wire
Take a photo before disconnecting if needed.
Step 3: Replace the Breakaway Battery (If Needed)
Most trailers with electric brakes use a small onboard battery.
Inspect for:
- Corrosion
- Swelling
- Cracked housing
- Low voltage
Install the replacement battery inside the battery box and reconnect wiring properly.
Step 4: Install the New Breakaway Switch
Mount the new switch securely to the trailer tongue.
The cable should be:
- Long enough for turns
- Short enough to activate before safety chains fail
Do not attach the breakaway cable to the safety chains.
It should connect independently to the tow vehicle.
Step 5: Connect the Wiring
Most standard electric trailer breakaway systems wire as follows:
- One wire to trailer brake circuit
- One wire to positive battery power
Use:
- Heat shrink connectors
- Weatherproof butt connectors
to help prevent corrosion and moisture problems.
Secure loose wiring with zip ties.
Step 6: Test the Breakaway System
After installation:
- Reconnect trailer power
- Pull the breakaway pin manually
- Attempt to rotate a trailer wheel or slowly pull forward
The trailer brakes should activate immediately.
Reinsert the pin after testing.
Important:
Never tow with the pin removed.
Step 7: Verify Battery Charging
Many modern systems charge through the trailer plug.
Use a multimeter to confirm:
- Battery charging voltage
- Proper power connection
A dead battery means the breakaway system may not work in an emergency.
Common Mistakes to Avoid
Avoid these common issues:
❌ Attaching breakaway cable to safety chains
❌ Reusing corroded wiring
❌ Forgetting to test the system
❌ Installing a dead battery
❌ Incorrect wiring connections
A properly functioning breakaway system is often required by law and critical for towing safety.
When Should You Replace the Entire System?
It may make sense to replace the whole system if:
✔ Battery is old or dead
✔ Switch is damaged
✔ Wiring is corroded
✔ Battery box is cracked
✔ Multiple components have failed
Complete kits are often faster and easier than replacing parts individually.
Keep Your Trailer Safe & Legal
A working breakaway system helps protect both your trailer and others on the road. Regular testing and maintenance can help avoid dangerous failures.
At Highway Trailer Company, we carry breakaway switches, batteries, battery boxes, chargers, wiring, and complete breakaway kits to help keep your trailer towing safely and reliably.