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Truck Headlight Connectors

Updated: Sep 12, 2018

Lighting is a tricky world, especially when it comes to plugging in the light to your truck. This guide will go through some of the basic connectors for headlights. While we only have a certain amount of connectors at our disposal, hopefully this will give you an idea of what you are looking for. A more in-depth video guide is on the way.

Connector #1 – H4 Connector

The H4 connector is inside a light assembly. It has 3 prongs: ground, low beam, high beam. Since it is either welded to the bulb itself or has wires that come off the bulb with the connector at the end, the purpose is to connect a bulb to a wiring harness. The wiring harness would then connect to the truck.

*NOTE H1 and H7 connectors look like an H4, but have 2 prongs. They serve the same purpose.

Connector #2 – Kenworth, Western Star, and Gillig Bus Connector

Moving on to wiring harness connectors, we have our 3 prong male. These are typically found on most Kenworth and Western Star trucks, and also Gillig buses. This connector is plastic, has 3 wires that are seated into the connector, a rubber gasket that acts as a weather strip, and a clip on the top to keep it in place. This controls the high and low beams on the light assembly.

Connector #3 – Freightliner, Navistar, and Blue Bird Connector

We now move onto the 3 prong female version of our harness connectors. These are typically found on Freightliner and Navistar Trucks and Buses. This connector is also plastic with a recessed portion that has the points of contact inside. All 3 wires come in from the back and are held in place by a plastic clip. The connector also clips on the connection point on the vehicle.

Connector #4 – The Mighty Peterbilt Connector

Our 3rd representative of harness connectors is our Peterbilt connector. It is literally a combination of the two previous connectors. Sometimes it will have a few more prongs depending on your truck. The idea is to have the headlights controlled by the male plug and the side marker controlled by the female plug. Leave it to Peterbilt to have the fanciest light connection.

Connector #5 – Good Old Fashioned Hard Wiring

Older style trucks will just be hard wired together. This also works in a pinch on newer trucks if you don’t have the time to go out and buy a new connector. You warranty may be voided, but at least you will have lights. On trucks, green is usually ground, red is high beam, and black is low beam. However, your mileage may vary based on your truck.

*This leads me to the disclaimer part of this article.*

While this is a basic and I do mean VERY BASIC guide to connectors, not all truck brands will match up to the connectors. There is no set rule that connectors follow. Sometimes a Peterbilt will use a Kenworth connector, etc. It all depends on your individual truck. In the end, look at your truck connector, see if it matches the pictures, and if it doesn’t it’s probably something I haven’t mentioned. There are so many connectors out there.

Also, if you do hardwire your truck, make sure you have everything done properly; we do not take responsibility for any damage caused by you and your wiring skills.

I hope this guide has been of some help to you. Let me know in the comments below.

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