Noted some more symptoms.

If I turn on the headlights and then use the cruise-control, cruise-control will work for the duration of the trip.

Is there any reason why cruise-control would be dependent on the headlights being turned on?

Remember, this is an 1993 E320T cruise control transplanted/wired to work in a 1988 300TE.

Could my mechanic have wired into the wrong circuit?

Thanks in advance,

:-) neil