What is a Trailer Air Supply Knob?

A trailer air supply knob is an essential component for any trailer that is equipped with air brakes. This knob is typically located on the dash of the truck and is used to adjust the air supply to the trailer’s air brakes. It is important to know how to properly adjust the knob as it can affect the performance of the trailer’s brakes. Without the correct adjustments, your trailer could become a safety hazard.

How Does a Trailer Air Supply Knob Work?

How Does a Trailer Air Supply Knob Work?

The trailer air supply knob works by adjusting the amount of air pressure that is sent to the trailer’s air brakes. The knob typically has various settings that allow you to adjust the air pressure up or down. It is important to properly adjust the knob as too much air pressure can cause the brakes to be too sensitive and make it hard to control the trailer. Too little air pressure can make the brakes ineffective and could even lead to an accident.

How To Adjust a Trailer Air Supply Knob

How To Adjust a Trailer Air Supply Knob

Adjusting the trailer air supply knob is relatively simple and straightforward. First, you need to make sure that the knob is turned off. This will ensure that the trailer’s brakes are not receiving any air pressure. Then, you can turn the knob to the desired setting. You can increase the air pressure by turning the knob clockwise and decrease air pressure by turning it counterclockwise. Make sure to adjust the knob in small increments until you get the desired air pressure.

When To Adjust a Trailer Air Supply Knob

When To Adjust a Trailer Air Supply Knob

It is important to adjust the trailer air supply knob whenever you are towing a trailer with air brakes. This will help to ensure that the trailer’s brakes are working properly and efficiently. Additionally, if you notice that the trailer is having difficulty stopping or it is taking longer than usual for the brakes to engage, you should check the air supply knob to make sure it is set properly.

Importance of Adjusting a Trailer Air Supply Knob

Importance of Adjusting a Trailer Air Supply Knob

Adjusting the trailer air supply knob is essential in order to ensure that the trailer’s brakes are working properly. Without the correct adjustments, the trailer could become a safety hazard and could lead to an accident. Additionally, if the air supply knob is not set properly, it could cause the trailer to be difficult to control. It is therefore important to properly adjust the knob in order to ensure safe and efficient operation of the trailer.



A trailer air supply knob is an essential component for any trailer that is equipped with air brakes. It is important to know how to properly adjust the knob as it can affect the performance of the trailer’s brakes. Adjusting the knob is relatively simple and should be done whenever you are towing a trailer with air brakes. Properly adjusting the knob will ensure safe and efficient operation of the trailer and can help to prevent an accident.