Ford Motor Company said:9.4 CHECK FOR OPEN SENSOR
Verify ohmmeter is on 20K ohm scale.
Measure resistance between RABS sensor Pins A and B.
Is resistance less than 2500 ohms?
I don't know. How can I tell? I do have a pump looking thing that the belt runs that sits right next to the oil fill spout that has a hose that connects to the vacuum manifold from which a hose runs to the power booster. I did check the hose that connects to the power booster yesterday for vacuum with my finger. The vacuum was almost not detectable but there was a slight vacuum. I don't know how much vacuum is needed.Just to verify what you have, is this a vacuum or Hydro-Boost system?
You are right. After I disconnected the pump hose from the vacuum manifold and ran it directly to the booster, it worked fine. :smile2: What else hooks into the vacuum on these trucks?I would say that your vacuum pump is shot. Either that or you have a massive vacuum leak.