Tekonsha 118412 4-Way Flat OEM Replacement Harness
Tekonsha 118412 4-Way Flat OEM Replacement Harness — Product description
Tekonsha's 118412 is the fix when your factory trailer harness has had enough. It's a direct 4-way flat replacement for the OEM wiring, so you get clean running lights, brake, and turn signals back to the trailer without splicing into your vehicle's harness.
The Tekonsha 118412 is a replacement for the 4-way flat trailer wiring harness that came on your vehicle from the factory. If the original has corroded at the connector, gotten crushed, or just stopped passing a signal to one of the trailer circuits, this is the part that puts you back in business. It's built to drop into the same spot the OEM harness lived in, so you're not re-engineering anything.
A 4-way flat handles the basics, and for a lot of trailers that's all you need. Running lights, left turn and brake, right turn and brake, and a ground. That covers most boat trailers, small utility trailers, and any setup that doesn't run electric brakes or a backup circuit. Plug the trailer's 4-way into this harness and your lights come alive.
Why replace instead of splice? Because the factory harness is matched to your vehicle's wiring, and a clean replacement keeps you out of the scotch-lock and electrical-tape business. Corroded trailer connectors are one of the most common reasons a rig fails a pre-launch light check, and a fresh harness with sealed terminals is the honest fix, not a patch that fails again next season.
Installation is about as friendly as trailer wiring gets. You're locating the factory connector, unplugging the tired harness, and clicking the 118412 into place. No cutting into the vehicle's main loom, no guessing at wire colors. If you can reach the connector, you can do this job in your driveway with hand tools and maybe a test light to confirm each circuit before you hit the road.
Tekonsha has been building trailer wiring and brake control gear for a long time, and the 118412 carries that same no-drama reputation. It's the part you want if you'd rather solve the problem once. One thing worth saying plainly: this is a 4-way flat replacement, so if your trailer needs electric brakes, a 7-way, or a charge line, you'll want a different harness. Not sure which fits your vehicle? Send us your year, make, and model and we'll point you at the right one.
Key Features
- Direct replacement for the factory 4-way flat trailer harness, no splicing into the vehicle loom
- Carries all four standard circuits: running lights, left turn/brake, right turn/brake, and ground
- Plugs into the same OEM connector location for a clean, reversible install
- Sealed terminals stand up to road spray, salt, and boat-ramp dunkings better than a taped splice
- Sized for trailers without electric brakes, including boat trailers and small utility trailers
- Built by Tekonsha, a longtime name in trailer wiring and brake controls
Why Buy from NVN Marine
- Authorized Tekonsha reseller, full manufacturer warranty
- NMEA member and ABYC certified, advice from real boat techs
- Same-day shipping before 3 PM ET on in-stock items
- NY headquarters and Fort Lauderdale flagship retail store
Technical specifications
| Title | 4-Way Flat Replacement For OEM Wiring Harness |
|---|---|
| Brand | Tekonsha |
| Manufacturer Part Number | 118412 |
| UPC | 016118058703 |
| Connector Type | 4-Way Flat |
| Harness Type | OEM Replacement |
| Product Type | Trailer Wiring Harness |
| Circuits Provided | Running lights, left turn/brake, right turn/brake, ground |
| Electric Brake Support | None (4-way flat carries no brake circuit) |
Frequently asked questions
What does this harness replace?
It replaces the 4-way flat trailer wiring harness your vehicle came with from the factory. If that original has corroded, been damaged, or stopped feeding one of the trailer circuits, the 118412 drops in where it lived.
Do I have to cut any wires?
No. It plugs into the same factory connector the old harness used. You're unplugging the worn one and clicking this in, with no splicing into your vehicle's main wiring.
What circuits does a 4-way flat carry?
Four of them. Running lights, left turn and brake, right turn and brake, and a ground. That's everything a trailer without electric brakes needs.
Will this work if my trailer has electric brakes?
No. A 4-way flat doesn't carry a brake-control circuit or a charge line. If you run electric brakes you'll want a 7-way setup instead. Ask us and we'll help you sort it out.
How do I know it fits my vehicle?
Fitment depends on your year, make, and model. Send those to us before ordering and we'll confirm the 118412 is the right harness for your rig.
Is it hard to install?
Not really. If you can reach the factory connector, it's a plug-and-play swap with basic hand tools. A test light helps you confirm each circuit before you tow.
