I had a cummins authorized mechanic replace my ecm in Arcada Ca. quite an education, {$3,500}. After 1000 miles, no cruse control or pac break. Took it to cummins mechanic in Phoenix, they said replace the TPS {$ 600}. Still no cruse {off and on}. After 2 years of cruse and pac break working off and on I took it to Sacramento Truck Center who specialize in in motorhomes {hard to find those that do this but be sure you do}. Motorhomes have a significantly different electronic engineering and the average cummings mechanic will not have the specialized experience which is why they all hate to work on our rigs. Over 20 years I have maybe 6 or 7 cummings mechanics work on my rig {only electronics as I am a licensed aircraft mechanic and do everything else myself } Sac has a mechanic that has specialized in motorhomes for 20 plus years, the best I have seen.-- John M PS, problem, bad ground intermit malfunction, hard to find.