Freightliner Cascadia: Park Brake Air Low, Brakes May Drag Warning

A common problem with the new Freightliner Cascadia is the "park brake air low, brakes may drag" warning.

When the system is operating properly, the warning will come on with the truck in gear and the brakes released if air pressure is dropping to 75psi or below.

When the system is not operating properly, and the switch is failing, it will stick and come on at higher air pressure readings, or possibly stay on at all times with the truck in gear and brakes released.

If you are getting this warning at pressures above 75psi, and there are no leaks in the system, the most likely problem is a switch called "brake pressure, low brake drag warning". Yes, Freightliner has a switch added to the system specifically for this warning. Why not simply use the low air pressure warning? Ask freightliner, I guess they wanted to complicate their trucks even further with unneeded parts.

To remove this switch:

1. drain all air from the air system.
2. remove the three trim panels below the steering wheel to access the switch.
3. disconnect the connector and unscrew the switch. This particular switch has a blue stripe on it, part number is 12-26771-000.
4. install new switch, reconnect connector.
5. veriy repair by starting truck and verifying warning turns off around 75psi.
6. reinstall the trim panels.

If you purchased all of the extended warranties from freightliner when you bought the truck, the part is covered under warranty. That said, the part costs around $50 from the dealer, and you can complete the repair yourself in under an hour if you have the part in hand.