Reviewed · Australian Shark 6 towing setups
Connected the caravan, boat trailer or illuminated bike carrier and found a dead indicator? Start by recording what works. A single failed lamp needs a different check from every trailer light going out at once.
This guide helps you inspect visible connections and prepare for a circuit diagnosis. It uses Australian terminology and the linked Australian handbook; check your own build, fitted towing equipment and current software before following a menu instruction.
Which trailer lights have stopped working?
| Symptom | Useful checks | What it does not prove |
|---|---|---|
| No trailer lamps work | Plug connection, shared earth, vehicle output and installed harness | That towing mode or a generic harness is definitely the cause |
| One indicator or stop lamp fails | That lamp, contact and individual circuit | That the whole harness needs replacing |
| Lamps dim or affect each other | Earth return and connections under load | That a continuity beep confirms a healthy connection |
| Fault began after an installation | New connectors, routing, circuit protection and compatibility | That a software update will correct an installation fault |
Do not rank the causes by popularity without evidence. A failed lamp, damaged plug, wiring fault and vehicle-side problem can produce overlapping symptoms.
What can you check safely while parked?
1. Inspect the plug and visible wiring
Secure the vehicle and trailer against movement on suitable level ground. Follow the vehicle’s connection procedure; do not move around behind a vehicle that could roll.
With the plug disconnected as instructed, look for bent or recessed contacts, corrosion, cracked housing and damaged cable entry. Check exposed trailer wiring for chafing near the drawbar and loose lamp connections.
2. Check each lamp function
Ask a helper to observe the left and right indicators, tail lights and stop lamps while the vehicle is safely stationary. Check other fitted lamps using the vehicle’s prescribed testing procedure.
Record missing, dim or intermittent functions separately. A single photograph of illuminated lamps is not enough to show that the connections remain reliable under each operating condition.
- The exact dashboard message or indicator colour.
- Which lamps fail and whether other lamps change brightness.
- Whether the fault began after new lamps, a plug repair or a harness installation.
- The vehicle’s build year, software version and fitted towing equipment.
3. Leave electrical measurements to a suitable test procedure
A socket that appears to have no power needs a circuit check, not a parts guess. Electronic outputs may require a load or use switching that makes a single unloaded multimeter reading misleading.
An auto electrician can check the earth return under load, the affected output and the installed harness. Avoid bridging contacts, feeding power into an unknown pin or probing unfamiliar vehicle wiring.
Do you need to activate Shark 6 towing mode manually?
The linked handbook describes automatic towing-mode activation when the vehicle is parked and the trailer cable is connected. Its manual detection control is under Vehicle → Towing Mode; indicator detection starts after 15 seconds.
This does not establish that every trailer circuit is disabled unless you first operate a separate switch. Check the actual towing status and use the instructions for your software version if activation fails.
What does the built-in detection tell you?
Use the detection routine to observe the functions it operates. Complete a visual check of the other required lamps as well; a routine that passes does not establish that every lamp, earth connection and brake circuit is healthy.
If the trailer warning persists, keep a photo of the message and note whether it changes after reconnecting. Those observations help the technician reproduce the fault without inventing a menu workaround.
Does a CAN-bus harness automatically solve the fault?
A product’s anti-error or CAN-bus wording does not diagnose why your lights stopped working. The label also does not, by itself, establish how the device communicates with the vehicle.
Incorrect loading or wiring can affect an electronic lighting output, but that is different from proving that a splice has back-fed voltage onto the CAN data network. Have the actual circuit checked before assigning that cause.
The handbook cautions against directly splicing the trailer circuit. Any aftermarket installation needs a vehicle-specific wiring plan and a compatibility check; a plug-in connector alone is not proof of manufacturer approval.
Repair the identified fault
- A failed lamp or damaged connector may need a local repair.
- An earth fault needs a sound return path.
- A blown fuse needs the underlying circuit checked.
Assess a replacement interface
- Confirm the build year and existing connectors.
- Check lamp requirements and output protection.
- Confirm its interaction with the factory towing functions.
A Shark 6 harness option to check
Vehicle-Specific Trailer Wiring Harness Kit with Anti-Error CAN Module
The public listing includes BYD Shark 6 — AU 7-pin. Ask us to confirm your build year, existing socket and towing equipment before ordering; use the vehicle-specific installation instructions.
View the Shark 6 AU 7-pin optionThis is an aftermarket option to assess after diagnosis, not a guaranteed cure for every light fault. For connector or installation questions, send us your vehicle details and plug photos.
| Item | Information to provide | Confirmation to request |
|---|---|---|
| Vehicle | Year, Australian specification, VIN and existing tow equipment | Exact connector and installation coverage |
| Trailer | Plug photos, lamp type and any adaptors | Compatible socket, circuits and lamp loads |
| Existing fault | Failed functions, messages and diagnostic results | Whether the proposed part addresses the diagnosed cause |
| Installation | Existing harness and any previous changes | Written instructions and post-installation function tests |
For current pricing, use the currency selected on the product page. The original draft’s AU$220 is not a verified Australian-market price, so this guide does not repeat it.
When should you contact BYD or an auto electrician?
Contact BYD for a suspected vehicle-side fault, a towing-status problem or guidance on a relevant software action. Ask an auto electrician to assess trailer connections and any aftermarket installation using the appropriate vehicle information.
There is no verified blanket OTA fix in this guide. Record the software version and ask BYD whether a release or service action applies to your specific vehicle and symptoms.
A trailer lighting harness also does not establish that electric brakes or a breakaway system work. Those systems need their own installation and function checks before towing.
What should you check before the next tow?
- Check that the plug is secured by its actual retention mechanism and the cable has safe clearance.
- Test all required lamps individually.
- Confirm towing status and investigate any remaining warning.
- Check brakes, breakaway equipment and the coupling as applicable.
- Confirm the loaded trailer and towing combination stay within the actual rated limits.
Do not assume a passed lamp check proves the trailer brakes work, or that every Shark 6 variant has identical towing equipment. Use the vehicle, trailer and fitted accessory specifications for the combination in front of you.
BYD Shark 6 trailer lights: frequently asked questions
Why are my BYD Shark 6 trailer lights not working?
Possible causes include a damaged connector, a poor earth, a failed lamp, a circuit fault or a problem with the fitted harness. Check which functions fail and when the issue started. The symptom does not prove that a universal harness is the cause.
My Shark 6 trailer plug shows no power. What should I check?
Inspect the plug and note the towing status and failed lighting functions. An unloaded socket reading can be inconclusive on an electronic output. Ask the technician to test the affected circuit using the correct vehicle information and a suitable load.
Do I always have to turn towing mode on manually?
Do not assume a separate manual switch is always required. The linked Australian handbook describes automatic activation when the vehicle is parked and the trailer cable is connected. If it does not activate, use the procedure for your build and software version.
Does the Shark 6 have a trailer light test?
The linked handbook describes indicator detection under Vehicle → Towing Mode. Treat it as a check of the functions it actually operates, then visually check the remaining required lamps. A detection routine is not proof that every lighting and brake circuit is healthy.
Can I replace a blown trailer fuse myself?
For a trailer light fault involving a blown fuse, the handbook directs the owner to a BYD dealer or service provider. Do not repeatedly replace the fuse, increase its rating or bypass it. The underlying circuit needs checking.
Is every spliced wiring kit incompatible with a CAN-bus vehicle?
A CAN-bus label alone does not establish compatibility or diagnose a fault. The circuit design, vehicle output limits and installation method matter. Follow the vehicle instructions and have the installer confirm the exact interface rather than treating any generic kit as suitable.
Which EVparts4x4 harness option should I look at?
The public product listing includes BYD Shark 6 — AU 7-pin. Confirm your build year, existing socket, installed towing equipment and lamp requirements before ordering. The listing is not evidence that fitting the kit will repair every trailer-light fault.
Will this harness also fix my electric trailer brakes?
A trailer lighting harness does not establish that the trailer brakes work. Electric-brake control and breakaway equipment need their own compatibility and function checks. Do not connect a brake-controller feed by guessing from a stop-lamp wire or a generic diagram.
Can a software update fix the lights?
That depends on the diagnosed fault and the update released for your vehicle. Record your software version and ask BYD whether a relevant update or service action applies. This guide does not establish a universal towing-mode software fix or release date.
Will a plug-in harness preserve my warranty?
A plug-in design is not a blanket warranty guarantee. Check the warranty terms and document the proposed installation. Australian Consumer Law guarantees are separate from manufacturer warranties, but that does not promise coverage for damage caused by an accessory or its installation.
The ACCC explains statutory car guarantees and manufacturer warranties. Keep fitment confirmation, installation instructions and invoices; do not treat “no wire cutting” as a blanket warranty promise.
