I have a 97 mariner magnum 225 efi with a Quicksilver 3000 throttle. My trim tilt works fine at the bow and on the motor. I can get the one on the throttle to work if I push on the back of the switch.

My question is if I get a blinker style one can I just run the wiring up to the bow trim tilt switch and splice in there ?

If not how do you wire these things?

Are you referring to the tilt/trim switch that mounts to the steering column?  If so, it would be a lot easier to disconnect the wiring at the throttle and splice in from there.  If you are not comfortable doing that, then using the bow wiring will be fine.

You have three wires going to the motor to operate the tilt and trim. Does not mater how many switches you connect or where you connect them, as long as they are all properly connected and in parallel with the three wires going to the motor. I have a total of four T&T swithes operating my motor

The wires going to the bow are probably running along the inside of the gunwall to motor.  The main cable to the motor should have a platic plug on it that's plugs into the the motor control handle and the wires going to the bow are spliced into that wire somewhere under the dash or near the control handle