1989 GMC Safari 6 cyl Two Wheel Drive Automatic 138000 miles
The parking brake set light is blinking even when there is no jumper on the ADLC (or whatever that acronym is). Three short/one long. At first the light would just stay on so I checked the switch--it was good. After a few days this series of flashes started and won't go away. I replaced the vacuum lines a few months ago when they cracked and caused really bad idling problems. Those are still good. All the research I've done points to the ABS system (Kelsey-Hayes RWAL & RABS Rear Wheel Non-Integral) as one possible problem, or the ECU. I can't find the specific code to help me on this. My one manual does not have them.