Testing and Troubleshooting a Modulite Vehicle Wiring Harness Video

It sounds as though there is a short or something is mis-wired. Using a circuit tester, like the #PTW2993, check the connection points in the vehicle side connector, to see if there is constant power on the running light circuit (brown wire on the…

What you are describing is normally the result one 1 of 3 issues: First, there could be some corrosion in or on the connectors on the vehicle or trailer side or both. Second there could be a bad ground. Bad grounds can cause all sorts of bizarre…

It sounds like there is a short that is drawing power to the driver side tail light. Since harness #118552 is a powered harness and is connected the the vehicle battery a short would draw power even with the vehicle off. The first thing you are going…

The most likely cause for the incorrect behavior of your trailer lights, where activating one turn signal causes all trailer lights to blink, is an insufficient ground (or a short to ground) on either the vehicle or the trailer. Since you re-wired…

Try improving the connection of the main ground wire of the trailer wiring harness. Make sure it is attached to a clean metal surface. Or you can run all of the trailer wires back to the main ground. This is actually the ideal solution. But you can…

The Hopkins Endurance 4-way Flat Trailer End Connector, #HM48110, that you referenced is the harness that goes on a trailer, not a vehicle. The 4-way connector for your vehicle is the Hopkins Endurance 4-Way Flat Vehicle End Connector, #HM48030. You…

On the 4-pole trailer wiring harnesses we offer for your 2000 Toyota Tundra, Tow Ready #118367 and Curt #C55367, the connection point is under the vehicle on the driver's side. There will be a connector to mate with the plug shown in the linked…

If you do not have a trailer connector at the rear of your 2000 Toyota Tundra you will need to start with a 4-way first. For that you would want the part #118367. Now if your trailer does not have brakes all you would need is the part #37185 as an…

It might be the tester. If the tester uses LED lights and it is a powered harness there can be some bleed off from the harness. This is normal and since LED lights require such little power draw they would light up a little. If you are using Curt…

With your plug-in trailer wiring harness, the Curt T-Connector Vehicle Wiring Harness part #C56274 on your 2018 Jeep Renegade then you will need to test the running light circuit leaving the converter box. If this wire has power while the…

Somehow you're getting bleed-over from the 12-volt accessory circuit to the lights on the trailer. This most frequently occurs due to corrosion in the trailer connector on the vehicle or on the trailer. Since you've recently replaced these,…

I suspect your problem is caused by a damaged or corroded trailer connector. Take a look at your trailer connectors, both the socket on your truck as well as the plug on the trailer. Look for green or white corrosion on the pins or sockets of the…