ABS problems revisited

[DICK MEYER <RSM@arlvax.arl.psu.edu>]

I'm still trying to diagnose an ABS problem in my `91 V8 5-speed (without
the benefit of a Bosch ABS tester).  As I mentioned before, a solenoid will 
start operating at very low speeds as I'm approaching a stop.  Lately, the 
system will switch itself off when driving at highway speeds (no braking).  
I'm reasonably sure it's a wheel sensor problem, but I Ohm'ed  each one and 
they all came up within reasonable values (1.26-1.28 kOhm).  I'll next check 
if one is shorted to ground.  I have a couple of questions:

1.  Is there any easy way I can figure out which wheel the system thinks is 
locking up?

2.  What does the wheel sensor itself output (i.e., a voltage or a frequency)?

I plan to take home a portable battery oscilloscope this weekend, if I can
figure out what to try to measure with it.  I'd appreciate any advice you
can give me.

Dick Meyer
Applied Research Laboratory
Penn State University
State College, PA 16804
rsm@arlvax.psu.edu