Re: 1985 PRESTOLITE TILT ANDTRIM RELAYS
You'll love this, it may not have relays, check the wire sizes at the T&T switch, if you have large diameter wires, a bit smaller than a pencil you likely have a directly activated T&T. This means the switch controls the T&T motor without relays. If they are small you have relays somewhere. If you have large wires continue on. The harness from the T&T switch to the T&T motor likely has three wires, red, blue, and green. The red connects to the center terminal of the T&T switch at the dash end and to the battery positive terminal at the battery end, blue and green go to the switch end terminals at one end and the motor at the other end. At the T&T motor end there is a pull apart connector, at this point the black wire from the T&T motor connects to the battery negative terminal. The most likely problem is the T&T switch. Check for 12 volts at each end terminal while you try the T&T switch, if one end is 12 volts and the other is zero volts replace the switch, if it's good at both end terminals disconnect the T&T motor harness at the back of the boat connector and check for 12 volts at the blue and green wires of the harness coming from the dash while activating the T&T switch, if both wires have 12 volts then the wiring from the switch to the connector is good. If you get 12 volts at both conductors of the harness then I would suspect that the T&T motor has one bad field coil since if operates in one direction. Check the harness connector terminals from the T&T motor, it should show continuity (low ohms) between the black and blue and then the black and green wires. If one shows low ohms and the other shows high ohms then the motor is certainly bad. Obviously you will check for damaged, corroded wires or connectors and other physical problems before replacing anything. One point, I can't see your boat from here so use this information carefully. Unfortunately the 3 wire motors use a series armature/field coil circuit do you can't reverse the polarity to make it run backwards like you can with a 2 wire T&T motor. Good luck.
