Air brakes need monitors. That is what the air governor does. It monitors the air pressure inside the air brake system. When there is enough pressure, it shuts the system down. When there is too little pressure, it turns the system on. That makes sure you always have the right amount of air in the brakes to stop.
The location of the governor should be on the passenger side frame rail and it is covered by what looks like a Mexican hat. However, some people move the governor to a more accessible spot to make it easier to adjust.
To learn more about this situation just continue to read our article. It has the information you want to know about so you can find your air brake governor. It is not a hard part to adjust but getting access to it may not be a lot of fun.
The location will depend on the manufacturer of the air dryer or air brake system. If it is a Bendix AD-IS air dryer, then the governor is attached directly to that part.
If it is another brand of an air brake system, then the governor is located on the compressor or close to it. The problem with the AD-IS model is that the governor is not adjustable.
Sometimes the governor will be remotely mounted because the standard location is too hard to reach. If that happens to you, then just follow the unloader hose back to the governor.
That hose or line will lead you directly to the governor. As we said earlier, some owners relocate their governors to make sure they have easy access. So if you are buying a used RV, then ask the current owner if he had his relocated and where it is.
The location for the governor on this model of air brakes should be between the on-engine compressor and the air dryer. Exactly where it is not specified but you should follow the air lines to find it.
Other Cummins ISX governors may be located in the rear bay doors, on the right hand side, just under the air filter. It is usually mounted to the chassis and not the engine.
A third owner reported that his was directly on the compressor. This information lets you know that the governor will be in different spots depending on how the RV maker decided where it should go.
It should be bolted directly to the compressor on the front side of that part. To find the compressor, it is usually located on the driver’s side of the RV at the bottom rear of the motor. Look under the fuel pump for it.
According to the Cascadia maintenance manual, this RV has a Bendix Air Dryer Desiccant Replacement. However, the governor is not listed as a part on that air dryer.
If you want to do your own maintenance work on this RV, here is the link to the maintenance manual. It comes with exploded diagrams so you can find the exact location of smaller parts.
Not all of the diagrams will be giving you an exploded view.
According to some mechanics, this part should be located on the firewall. It is a head-scratcher of a location but that is according to the general textbook covering Volvo engines, etc.
Another owner has seen it but he thought it was a weird location and forgot where that location was. The best thing to do is think about the normal locations and then look elsewhere to find them.
If you are going to do the work yourself, do not buy the part from the dealer or RV maker. Go to the local auto parts store and save yourself about $50 on your costs. The quality is the same so you are not losing out by buying cheaper in this situation.
If your air brake system has an AD-IS air dryer, then the governor should be mounted to the side of it. This governor is not adjustable and if you are having problems with air pressure, you would have to replace the part.
The DD15s do not have a lot of room to work with and the compressor is mounted in the rear. That is why the governor has been moved to near the air dryer.
If you can work it out, you may be able to relocate it to somewhere more accessible. Just ask a good mechanic about that option. He may know of some tricks to make the governor more accessible.
The word is that if it is not located on the compressor, then it should be found on the firewall. Also, some owners relocate their governor to the passenger side firewall to make sure they can access it easily.
Another location will the passenger side frame rail and it is supposed to be very difficult to get to. One thing to keep in mind, the governor on the Mack truck may not look like the governor on other vehicles.
Some people do get confused as they do not recognize the part even when they are looking right at it. You may have to look at a Volvo governor before you will recognize that part on a Mack engine.
Finding different parts is not always fun. Nor is it like a treasure hunt where you get a big reward after finding what you are looking for. Finding the governor on an air brake system can be frustrating as it can be relocated by a previous owner.
But once you find it, you may or may not be able to adjust the air pressure. Some Bendix models are non-adjustable and your only course of action is to replace the part. Buy at the auto parts stores and save.