Johnson Trim Motor Issue

[otis44]

Motor is a 79, 75hp. Didn't come with power trim & tilt, I picked up a used hydraulic unit and relay box. The motor is a 2 wire system. Problem is this; the trim motor will not run nor lower the cylinders from the switch at the controls or the switch I mounted on the engine. It will run and raise the cylinders from either switch fine. If I hook the motor directly to the battery it runs, lowers and raises the cylinders as its supposed to.

I have swapped both relays with two others from another engine which made no difference. I am getting 12.7 volts at the trim motor on both the up and down side when either switch is depressed accordingly. It appears the relays are working, wiring, etc is correct. I have ohm'd the motor with a digital meter. I get a 0 reading on all settings except for the lowest one on the meter, which shows 0.4 ohms. Is it possible for the motor to work directly from the battery, but due to some internal issue not work through the relays, switches etc?

Part of me wants to rebuild or replace it regardless due to not knowing its age, but I hate to spend money I don't have to. Thanks for any help.

[ChampioNman]

If the motor operates properly by connecting to the battery then the motor is working correctly. You need to check your wiring from the relays to the harness to the motor.