Hi all, i'm new to this forum.
You know what, how about you bypass all the wiring from the front ABS sensors with alligator jumper test clips, for testing purposes only.
All front sensors are on the 4 pin plug.
Refer to the service manual.
FYI... We've now got a service manual for the ABS braking system for the 2nd Generation trucks. Thanks to Diesel Pl on CF.com
http://forum.mopar1973man.com/files/file/92-2nd-gen-abs-braking-system/