Wrench light and battery light
 

Hello. . This is my first time posting so go easy on my mechanic lingo issues. We have 2006 E450 6.0 diesel shuttle bus we purchased used. Has been running great after a general service and minor repair to turbo by certified diesel mechanic. Recently when we ran long distance the wrench light comes on. We stopped for a little while and it would not come back on until we drove for a while. Always goes off when we cut off the bus and not return until we drove some distance. Lately the battery light random flashes. No issues however other than the light flashing randomly. Until today. . Battery light was on at crank. Drove about 35 miles and the wrench light came on vehicle went into limp mode ( I assume) and we barely made it home. Every time we pressed the gas it would faulter. Not sure if its battery or alternator or both or neither. Just needing ideas as not to chase my tail. Thanks