<https://www.bigmacktrucks.com/topic/25721-cab-air-ride-wont-raise/#comment-124767>
<http://schema.org/text>
"Just check the ride height valve under the back of the cab, it should only have 2 air lines going to it. One is the supply and the other is delivery to the air bags. If you are getting a good supply of air to the valve, then disconnect the height control rod on the valve and move the lever up and down manually and see if raises the cab or not. If this is the case then you have a crook valve. If you are not getting supply to the valve then, as mentioned earlier it will be a priority valve on the tank. \n"
<https://www.bigmacktrucks.com/topic/25721-cab-air-ride-wont-raise/>