Re: Relays on tilt/trim
With an 88 engine, the trim motor should be two wire. before you run extra wire to the dash, disconnect the green and blue wires running to the motor. NOW with one wire grounded, touch the other to the battery cable on the battery side of the solenoid. If the motor runs, then at least one relay is bad OR the switch itself is bad. Reversing the wires will have the motor turn in the opposite direction. If it functions in both directions, then check the switch and relays. With a three wire motor, use black for ground and alternately touch each colored wire to the battery positive.
If you insist on running separate wiring and bypassing relays--not really good engineering practice --I do not recommend it, in fact, I hope to dissuade you, but it is acceptable--The old 3 wire system without relays used #10 wire. The motor can draw up to 30 amps.
HOWEVER: Because the two wire motor uses relays and because each wire is at ground potential for each direction, wiring a 2 wire motor without relays is difficult. Simply put, when green has power, blue is at ground and the tilt system goes down. When blue has power, green is at ground, the motor turns opposite, and the system goes up. The relays do the switching for you in addition to allowing you to use only low amp signal power at the dashboard switch.
Look at some of my previous answers to tilt/trim posts. In the last one I even gave NUMBERS of relays that can be found in junkyard autos. These relays are standard and can be found (without the mounting ears) in GM and Ford vehicles.
With the three wire motor, Each color wire is powered for one direction only and the black wire is ground. This motor WAS the one that early Chrysler wired without relays. I never liked the fact that full motor current was put through the dashboard switch. Lots of amperage and sparking at the switch. This shortens switch life.
With a little thought, the same relays used on the two wire motor can be used for a three wire motor. All that needs to be changed is to NOT wire the default ground on each relay. Thus: now it is possible to use low amperage signal current to activate the high draw motor. MUCH BETTER!
