1998 Freightliner classic xl

Im working on this truck and I'm very confused. The oil pressure light and the water temp. light come on when the A/C is on and when the jake brake is on. Now heres the really confusing part when the truck is running and the a/c and jake brake are on the buzzer goes off ect., if you turn the wheel it goes out. I tore the dash and the steering wheel apart and fount no wire touching the steering column or and no bare wires. I checked the wiring harness going to the ecm and ever other wire i thought was going to be the problem and nothing. The motor is a N14 Cummins. Has anyone else run into this problem? Any help is appreciated.