cruise control fault
 

I have a 96 e300d that new to me , trouble is when i put cruise on the check engine light comes on (CEL). after a couple of cycles it goes off and will not come back on untill i hit cruise on. i have code reader and it reads no codes. car has 110,000 runs great cruise also works well, no issues. any ideas, i have manual but it has no trouble shooting for cruise. also does the cruise have a dash light when it is on?
Thanks