Its all connected somehow; Sport Mode, Cruise Control, Low Range Lights

I have just bought a 1995 4.6 HSE Auto which has been used as a golf club conveyance for all its life and has (probably) never been in low range. Predictably the motor to shift ratios is not working but the lights are baffling me! When I had the test drive, the lights and beeper on the shift console worked perfectly (although they didn't stop beeping and shift to low range) and the 'Sport Mode' red indicator light worked fine, as did the cruise control. Now, all three are not working (unless at first start up when everything is cool - I live in Malaysia so normal ambient temperature is around 30 degrees centigrade).

I've read some posts that suggest heat might be a factor in connectivity but has anyone had this fault and found a solution. Another factor was that between the test drive and my taking possession, the switches for the cruise control on the steering wheel were replaced by a dealer - how are these three separate items connected? Have they forgotten to connect something?

The obvious solution is to take it back to the dealer/previous owner but its a bit complicated; they changed the switches without authorisation and he refused to pay the bill so I want to be forearmed with a bit more information before I wade in!

Any information would be much appreciated - Thanks

Thanks for all your helpful replies and suggestions but I've sorted it now...

I was concentrating on the BECM but it was the cruise control ECU that was the problem; the connection had become loose, once I pushed it in, everything worked. Still not sure how the low ratio indicator lights and the sport mode light were connected though but they are now also working.