1999 E-350 ABS and brake light on

My ABS and brake lights came on soon after I bought this van. Its like a big secret when you ask anyone about the abs system.The lights came on soon after I hooked up my trailer lights with a trailer with electric brake controller.I have dissconnected all of that includeing batt. to clear code but they are still on,also when they are on the cruise control does not work.An employee drove the van and left the parking brake on some.After that the lights went off and everything seemed to work fine,for a week or two .Now its back to the same problem. Any suggestions will be welcome Thanks