Charliep,
Just yesterday I installed the ECM operated Pacbrake control system. My ECM pin #20 was already activated also.
I did have the 799 reflash also.
Guess I saved a trip to Cummins.
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1998. 5; 24v,3500,4x4,SLT,QC,5 spd,3. 54LS, 4 whl. antilock, all options available when ordered, 18k lb. Reese full tilt 5th whl. hitch, oem full length diamond plate running boards, eyebrows & hood dam, bed edges,bedhooks plus Rhinohide liner, Pacbrake, britebox,"deepdish"mats, matching topper shell, Sandstone(looks gray to me) & camel leather, stainless fender eyebrows, chrome(and road tar) exhaust turndown pipe.
brush guard, SPA digital boost/egt gauge and pillar mount.
Lowered rear end 4" to set truck level.
See My Truck
1980, W200, regular 4 door crewcab, 360 gas, auto, 68k original miles, 4 coats of Zeebart but losing ground to the saltwater anyway.