Shuttle valve electrical failure

mastercamper

Well-known member
Nov 18, 2006
997
24
Erwin TN
Chasing this down. I’ve been having issues with a wheel speed sensor that I replaced and had to wire in since it didn’t have a plug. Thought I had it squared away and this came up. I did the shuttle valves a few years ago. 3 amigos come and go have since I’ve owned the truck. Usually I replace the wheel speed sensors and that fixes it for a while. Started having some issues when the brakes would squeal and 2 of the 3 would come on and go off when I restarted the truck.
 
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special ed

Well-known member
Apr 11, 2012
225
139
Elsinore
Replace the shuttle valves and re wire them out of the modulator. Search option B and you will find the information. Basically the shuttle valves are ohms to ground from the computer and dont need to be wires through the abs modulator.
 
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special ed

Well-known member
Apr 11, 2012
225
139
Elsinore
OK i feel like typing now. Shuttle valves are the switches on the bottom of the abs modulator, the computer is looking of ohms to ground through them. Either the wires are broken or the contact in the modulator has failed. The fix is to wire them outside the modulator. I drill a hole in the bottom of the shuttle valves and solder and shrink tube longer wires on. It does not matter which side goes where but one wire gets connected to the yellow green stripe wire running to the modulator and the other goes to a ground anywhere, i use the bolt on the ac line right there next to it. Use a new set of switches because the old ones will have cracked exposed wires on it.