Chrysler Repair: 90 5th Ave.: ABS wheel sensor problem

Question
QUESTION: I have 1990 Chrysler New Yorker 5th Ave. with what appeared to be a faulty RF wheel speed sensor on an Bosch ABS system.I found a used one in Arizona, and had my Chrysler mechanic install it.( Car kept performing a self check on system, and computer hook up diagnosed a wheel speed sensor problem). However, after completing the installation, the car continued with the self check and the problem remains! Now what? The mechanic and are stumped!Whats the problem, and how can the problem be fixed? HELP!!!!!! I'm pulling my graying hair clean out, and don't want this car to turn into a complete money pit. Oh.....this problem is only on the RF wheel.

ANSWER: Hi Mike,
Have you checked the continuity of the wires from the sensor to the ABS controller? According to the '90 wiring diagrams the right front wheel abs sensor has a pair of white wires that are individually connect to pins 6 and 7 of the 60-pin plug at the controller with no splices involved. So check the continuity of each wire, you will find one goes to pin 6 the other to pin 7.
That controller is under the battery tray and the plug is accessible from under the car. It is mounted on the inside of the frame rail and the connector appears to be above it, near the clamp for the transmission cooler line which runs past it. Remove the clamp for access to the plug. (The controller location is based upon my '91 shop manual)
The other possibility is that the tone wheel has too much run-out so the distance between it and the sensor is not correct. It is supposed to be no more than 0.25 mm (0.01 inch).
I think one or the other of these two possibilities explains the problem.
Please read the PS (below) and respond to it.
Thanks,
Roland

---------- FOLLOW-UP ----------

QUESTION: Yes, continuity is fine. Car has been worked by a 36 year ASE certified Chrysler mechanic. I ask him.So, now what? Dump valve? Module? Computer?

Answer
Hi Mike,
Did the mechanic check that the tone wheel is not out round or dented such that the spacing is greater than 0.25 mm?
Not only the continuity of the wires should be checked but also that they are not shorted together or that neither wire individually is shorted to ground, even though continuity to the pins is shown. Other than that and the tone wheel/sensor spacing, the last possibility is the CAB itself.
Thanks for the additional rating/nomination.
Roland