Electrical Wizards Needed - Inquire Within
Thread Starter
|
Postmaster
Joined: Apr 2001
Posts: 3,818
Likes: 3
Electrical Wizards Needed - Inquire Within
How does the reset valve switch on a RABS unit function?
The troubleshooting procedure for a flash 4 code for the RABS valve begins with a continuity check between the reset valve switch connector pin and the body of the RABS valve unit.(Which should be over 10K ohms). Both the original suspected unit and the boneyard replacement show up as 0.0 ohms resistance. Obviously to have continuity, the reset valve must ordinarily be grounded internally to the valve body. A literature description about the functioning of the RABS valve states the reset switch works when there are unequal pressures between master cylinder and rear brake lines BY GROUNDING which interrupts the logic circuit of the computer modeum. This would seem to imply the normal state would be "open" (non-grounded). I have a hard time believing the Ford factory manual would have you test for something that can't be done. On the other hand, both units are registering zero which tends to confirm the "open" position findings. Can anyone explain this discrepancy?
The troubleshooting procedure for a flash 4 code for the RABS valve begins with a continuity check between the reset valve switch connector pin and the body of the RABS valve unit.(Which should be over 10K ohms). Both the original suspected unit and the boneyard replacement show up as 0.0 ohms resistance. Obviously to have continuity, the reset valve must ordinarily be grounded internally to the valve body. A literature description about the functioning of the RABS valve states the reset switch works when there are unequal pressures between master cylinder and rear brake lines BY GROUNDING which interrupts the logic circuit of the computer modeum. This would seem to imply the normal state would be "open" (non-grounded). I have a hard time believing the Ford factory manual would have you test for something that can't be done. On the other hand, both units are registering zero which tends to confirm the "open" position findings. Can anyone explain this discrepancy?
Thread
Thread Starter
Forum
Replies
Last Post
jay_s5
1987 - 1996 F150 & Larger F-Series Trucks
11
Nov 23, 2004 04:49 PM
