Electrical 579 Family
Peterbilt Motors Company 7-16
Air Solenoids
Air solenoids are the devices that translate the electrical signal into physical change that controls the air pressure in
various circuits. The air solenoids are mounted to a bracket outside the cab. The solenoids are designed to stack on
each other so that they share a common air supply rail which reduces the amount of air lines on the vehicle.
Air solenoids used on the vehicle are both of Latching and Non Latching types.
TABLE 7-2. Air Solenoid Types
Requires a signal voltage to close or open a solenoid.
Will remain in position if power is disconnected.
Physically, these require 2 spots on the bank compared to
a non-latching valve.
Requires 12v to change a valve from its normal position.
Will revert back to its normal position if power is
disconnected.
For safety reasons, certain circuits are designed with latching type solenoid valves. These circuits include but are not
limited to:
1. Air suspension dump (tractor and trailer)
2. 2 speed rear axle control
3. Liftable axle controls (both on the vehicle and on the trailer)
4. Workbrakes for winches
The aftermarket installer/final vehicle manufacturer needs to decide what type of valve to install and ensure that the
documentation to the operator provides them with enough understanding of how the customized switches work.
NOTE: General air accessory, when ordered from the factory, is wired to a non-latching solenoid. Therefore,
general air accessory options will reset when the ignition is turned off. If a latching solenoid is installed on a
“furnish by owner” air accessory, the installer will need to document how the system operates.
