A 2004 when you first crank up the ABS light comes on and the alarm will ding, then it will go out after maybe 20 seconds. Anybody have any ideas what it may be? Thanks for any help.

All I can say is check all your wiring and grounds... The ABS module on the older truck is right on top of the trans hump. But becareful and disconnect the batteries for at least 15 minutes before messing with any connector. This will prevent a accidential discharge of the ABS system.