Rear Drum braked pickups have Rear Wheel Anti Lock or RWAL.... totally different to abs, sensed by a tone wheel on the centre section which also reads MPH for the speedo. RWAL is not abs as all it can sense is what the crown wheel is doing and not what each wheel is doing.
So RWAL measures what speed the crownwheel is doing compared to the front discs, if the rear is slower it reduces line pressure until they equalize
Pete.... the year of your Durango... I'd say it's full ABS...sorry.... time to grovel underneath and check wiring and any tone wheels and sensors for damage
I very much doubt you will get codes by any of the so called ignition switch rubbish, after a certain year Chrysler caught on to the fact that if they made it impossible for the guy in the street to get codes it means more $$ for them... sure they stopped the ignition switch deal around 96/97... my ram is 98 and it's a scanner or nowt, it's also RWAL so reletively simple

the 2001 ram I had was full ABS and a nightmare
scanner here
http://www.bowserelectronics.com