to add to what brewski said
remember the MIB controls the circuit by switching the negative to the contactor on, so when you check the voltage it should be there until the contactor is switched on, then it will drop to 0 volts or near 0.
Also i don't currently have a wiring schematic for this truck handy but i think on some trucks the steering circuit was triggered by a switch on the foot pedal that supplied a signal to the MIB telling it that someone was on the machine and the pedal was pressed so it completed the signal to steering to allow it to turn on the contactor to activate the steering motor, earlier models just turned it on when the key switch was turned on, pre MIB machines.

Since i do not have my manual on this machine i'm just making an educated guess from memory. ;o)

Put a volt meter on wires 10 and 36 at the steering contactor. If there is voltage and the contactor does not close replace the contactor. If you do not have voltage check continuity of the wires. If wiring is good, replace the MIB. Wire 36 runs from the coil to pin 2-12 on the MIB. Wire 10 is a keyed positive.

The early trucks used a relay to control the contactor. They eliminated the relay on later trucks. I believe the later trucks had the driver for the contactor in the controller.

No power steering.
When you say relay are you talking about the main function contactors or are there relays that trigger the contactors?
ty

Power steering and or traction relay coil fault. Is the power steering working? If it is you may have a MIB board failure. The traction relay was not used after MIB software version 1.02.