My heat wont come on in my chevy 1994 pick up truck. No power to the controls

You forget to check coolant flow to the valve and is valve closing/opening... is actuator working? very often problem is with the valve "freezing" in closed position (calcium deposits), check the valve...

if no power to the controls and you are sure thay are electric - check stage by stage where power is going. use continuity tester (12v bulb with 5m wire attached...) to determine where is break in circuit.

connect one end of the wire to negative terminal on the battery and then step by step touch fuse, switch (all positions if it is multiselector), valve terminal - if you have current flow, and valve actuator is electrical - it maybe faulty.

you did not provided exact model - and therefore only general advice was provided, if you find it useful - do nto forget to vote...