Here we go again
 

From prev post found a used pcm from a 04 f350. installed ran great check engine light went off trans shifted good. only thing that did not work was the tow hall button would not down shift. I figured this was because of the diff in the gear ratio 550 has 529's 350 411's? Any way used truck for few mounts no problems. Loaned it to a friend, he pressed tow hall and left on 50 mile trip. About 10 miles in trans started acting up slipping weird shifts loss of power so no. Made it there 3 hours later go's to return will not crank. Knocks on pcm, batt cables, some how starts makes it home but will not shift out of 3rd gear 45-50 mph all the way. gets here on reverse. Next morning will not crank, jump the starter fires right off. Take truck to dealer to reprogram pcm but will not communicate pcm/tcm fail. Bring it home truck runs, drops to idle, restart runs again, tow haul light flashes. After some testing have no ground to the starter relay once again, but if I jump a ground to it will run. Am I just looking for a bad ground wire once again and where should I start?