[900xj]

(In France sorry for the mistakes)

Edit : Sorry i just see in your case it's a diesel so a bit different but maybe same cause.

When i baught my 75 (kv6 2.5), cruise control didn't work.

I had light on the console but no light on the dashboard.

After reading forums, I spent time to look on brake pedal (auto box), checked all fuses, looked in the motor bay actuator assy, and behind the steering wheel buttons or console button (i had others), try with toaf, etc., but nothing.

If it was the brake pedal switch your brake light should always be on normally.

It was the cruise control unit (ecu) and its interface behind the glove box. I solved ti with good advices from a french member who guided me on possible causes. I baught them second hand on ebay and all is ok now (wich one had a problem i don't know i replaced both).

Maybe same thing for you if you can try with an other owner for a test.

(Same thing for my keyfob not working, it was simply the receptor out of order, near the hand brake, after searching for a moment too. Bought second hand, plug and play and then perfectly ok)