help with p38 diesel cruise control not working

please move if its not in the right area. i have the p38 1997 diesel and it has been converted to coils from the airbag suspension. the cruise control will not work and the light on the cc switch will not light up, does it require the vacuum style CC system or does the diesel have the different system as ive found the cruise control switch relay but no control module next to it. and theres no plug under the dash for me to simply add it back.

any help would be great full
thanks
oliver