I have offshore controls with the trim switch in the throttle and the switch seems to work intermittently.
It will trim down but not always up. Any ideas where to begin to look?
Is that the only switch you have? If not how does the other work?
The switch goes to a pair of trim pump relays from there to the pump motor.
Relays can and do fail I keep one in my boat tool box.
I would try replacing the trim relays
A volt and amp meter can help you solve your problem.
Start at the power connections make sure all connections are clean and tight at the battery then at the trim pump and relays. Trim switch will generally have three wires a red or purple hot going to the switch and two output wires the blue wire for up and a green wire for down.
I use a amp meter in the circuit to test for excessive trim motor current draw, from a bad motor that can overload and ruin the power relay
Intermittent problems can be a real bitch, I have hooked up extra jumper wires and a couple test lamps. To find signal problems that fail under operating conditions.
Thank you, I will check the connections and go from there.