Attwood Marine Trailer Light Circuit Tester, Inline, 4-Way
Got questions? Ask an expert!
Know someone who needs this?
Share it with your crew or mechanic.
Overview
The Attwood Marine 14133-6 is a trailer light circuit tester used to check common lighting circuits before you start pulling apart a harness or replacing lamps. It plugs into the wiring harness and uses indicator lights to show where the fault is, helping you sort out taillight, ground, and left or right turn-signal issues.
Its 4.75 x 3.5 x 0.5 inch size makes it easy to keep in the tow vehicle, glove box, or trailer tool bag. For boat trailers, it gives you a quick way to check the lighting side before a ramp run, after rewiring, or when an intermittent light fault starts showing up on the road.
Key features
- Inline circuit tester for trailer light wiring checks
- Indicator lights help identify faults in taillight, ground, and left or right turn-signal circuits
- Compact 4.75 x 3.5 x 0.5 inch form factor that stores easily with trailer spares and tools
- Useful for troubleshooting before towing, after connector service, or when one side of the trailer lights stops working
Compatibility and fit
This tester is meant for trailer lighting diagnostics, not as a replacement harness, adapter, or light assembly. The main fit point is the connector style on the trailer wiring, so it is worth checking your trailer plug and tow-vehicle socket before ordering.
On a boat trailer, this kind of tester is helpful when you want to narrow the problem down before replacing bulbs, cleaning grounds, or opening up the harness. That can save time when the trailer has been exposed to repeated launch and retrieval cycles and the issue may be in the wiring rather than the lamp itself.
Use and troubleshooting
Setup is straightforward: connect the tester to the trailer lighting wiring, then read the indicator response for the circuit you are checking. It is a practical tool for seasonal trailer prep, post-repair checks, and pre-trip inspections when you want to confirm the lighting system is working before heading to the ramp or back home.
This is a good match for boat owners who trailer regularly and want a simple way to isolate common light-circuit faults without carrying a larger electrical test kit. It also fits well in a small onboard locker or tow-rig tool bag where space is limited.
Shipping
We ship worldwide from the United States. Rates are calculated at checkout based on destination and package weight. Some items include free shipping, which will show automatically. Not every product is eligible for international shipping; checkout will confirm eligibility. We do not ship to PO Boxes except through USPS, and not all packages qualify.
Processing and dispatch
Most orders are verified, packed, and handed to the carrier within 1 to 2 business days. Some products may need extra handling time or ship directly from the manufacturer. For certain international orders, inventory transfers between warehouses may add time. If any delay is expected, we will let you know the dispatch date.
Delivery and tracking
Deliveries are handled by trusted carriers such as USPS, UPS, FedEx, and DHL. Estimated arrival times appear at checkout and depend on your location and the service you choose. These are estimates and can be affected by customs or carrier disruptions. A shipping confirmation with a tracking link is emailed when your order ships, and tracking may take up to 24 hours to update. You can also view tracking in your account.
Duties, taxes, and support
International customers are responsible for any customs duties, taxes, and fees charged by the destination country. If these charges are refused and a shipment returns to us, the carrier’s return cost and any re-entry customs fees will be deducted from the refund. If your order is late or you need help, contact cs@qualityboatparts.com and we will assist you.
Quality Boat Parts is a reseller. Many items include a manufacturer’s warranty, and all warranty service is handled directly by the manufacturer. We do not manage or administer warranty claims on behalf of customers.
Warranty terms, coverage, and duration are set by each manufacturer. Issues involving defects, repairs, or replacements must be addressed with the manufacturer’s support team. When available, the warranty period is listed on the product page. If it is not shown, contact us or the manufacturer for details before purchasing.
To start a claim, the customer must contact the manufacturer and follow their process. Keep your proof of purchase and original packaging, and register the product if the manufacturer requires it, as these are often needed for warranty service.
We are happy to help you find the right contact or documentation, but we cannot decide outcomes or intervene in claim resolutions. For guidance, email cs@qualityboatparts.com.