Rear only. One sensor on the differential - none on the front. The controller has one brake line going in, and one coming out - no others. The controller also doubles as the front/rear proportioning valve, according to my manual.

 

When did dodge start using a wheel speed sensor on the front for the speedo???? I thought that was on the third gens. Have a look at the front wheels, see if either side has a sensor.....

 

As mentioned, rear ABS only. One speed sensor on the rear differential. No sensors on the front wheels. The hydraulic ABS metering valve (attached to the ABS electronic control) only has one brake line going in - and one coming out, and the one coming out goes to both rear brakes.

 

Wonder if it's the controller that is bad.....

 

As mentioned earlier, my Alldata diagram was incorrect in showing the brake pedal switch. But where it WAS correct was in its illustration of the fluid level switch. When you read suggestions online to either disconnect or jumper the two-wire connector going to the fluid level switch, those suggestions will lead you down various incorrect paths. The correct path is this... I'm guessing there is a voltage divider circuit with one unseen resistor within the ABS controller, and another resistor (approx 10K ohms) across the two fluid level switch contacts. With my meter reading the resistance on the two pins of the switch, all I had to do is tap or shake the master cylinder reservoir, and it would go "open". With the switch faulted, I'm sure the controller will see the voltage go out of limits - giving me the chime and lights on the dash. Being a voltage divider explains why just removing the connector on the master cylinder will not do anything.
How I got there was to connect my scan tool and drive with 3 data PIDS showing on the tool - including the switch status of the brake pedal and the fluid level switch, along with vehicle speed (to verify rear sensor operation). On a 40-minute test drive, I happened to catch the fault with the fluid level switch when its status changed from "open" to "closed". It was a very intermittent fault.
Apparently, you can't just change the switch. You can either replace the reservoir only (which includes the switch), or the entire master cylinder. The switch by itself isn't serviceable. I found it cheaper (but longer shipping time estimate) to get the reservoir/switch from Mopar, than it was to get the entire master cylinder from the various online discount parts suppliers. It should be here in about 2 weeks.

 

I've got a spare used reservoir (likely from a 2004) sitting in the garage you can have for shipping if you'd like to have it quick - PM me. If its a switch, can you just take the plug out and connect the wires and verify its your solution?

 

Ah, bummer. I've already ordered one, and it's well on its way.
Thank you for the kind offer.