Which relay controls the starter for 1989 Mazda truck?

There are no relays that have any affect on the truck starting.If for some reason the truck has a starting issue I will list some.One battery is weak,or bad connections.Next alternator is not charging to full capacity.Starter solenoid is either bad,or has dead spots not engaging the starter when starting.Could be a multitude of things like bad ground wires from fender(rhs) to subframe,to block,or bad wires,coil or ignition control module(under distributor cap).Even a worn out ignition key cylinder where the key starts the truck can wear out creating a bad,no start scenario.Hope this gives a better answer to the possibilities of a no start.However start SIMPLE check the obvious battery,alternator(even alternator belt loose) and ground wires.Advance auto and and auto zone do free charging and battery checks to help isolate a issue in this area.