Alpha trim wiring.

[dozerII]

I have a 1986 Starcraft with a 4.3 Mercruiser, Alpha drive. Eng. #OC519811, transom OC639702, drive OC642898.
I am in the end stages of a complete rebuild on the boat and tring to figure out the wiring. I have installed new Sensor and limit swithes. The boat has a toggle trailer switch on the dash Spring loaded three position, and a shifter mounted trim in/out switch. Before the rebuild the dash mounted switch would lift the drive and the shifter one would lower it. On the trim pump there is a round three female plug that had nothing plugged into it and only a green and blue wire going to the solinoids. I would like to wire this up so the dash and shifter switchs do the jobs there supposed to. I have searched numerous threads and can'seem to find the right wiring diagram, none of them seem to have the right color wires to coinside with my harness.
Any help would be appreciated.

 

[dubs283]

Re: Alpha trim wiring.

you need the correct mercruiser manual for your drive, most likely #6 - i do not have any links for finding them but others here do

if you go to the non-repair forum for i/o engines and start a new thread asking for a manual, post your drive serial number and someone will help you

read through the trim wiring section and if none of it makes sense ask a question or two

 

[Don S]

Re: Alpha trim wiring.

You have a non standard setup from Mercruiser. Below is the troubleshooting chart from the service manual that has the wiring diagrams in it. The way your system should work, is the up and down button on the shifter should run the drive down and up as high as the trim limit switch will allow it. Then, you would also activate the dash switch and the up button on the control to bypass the trim limit switch to raise the drive up to the trailer position.
These drawings show a 3 button switch. The top and bottom buttons would be the up and down on your shifter handle, the center button would be your dash mounted momentary switch.

View attachment A1,MR,RTrim Troubleshooting.pdf

 

[dozerII]

Re: Alpha trim wiring.

Thanks a bunch Don, I will see if I can figure it out now.

 

[Don S]

Re: Alpha trim wiring.

Thanks a bunch Don, I will see if I can figure it out now.

If you can't, just ask, I can.

 

[dozerII]

Re: Alpha trim wiring.

If you can't, just ask, I can.

Okay Don, I'm asking. I'm pretty sure the wiring harness is a Mercruiser one, as there is no butchered splices or jury rigged conections in it? The control is a Hi-Lux brand, and has a red, blue green for the trim, as well as the two yellows for the neutral switch. The Merc wiring harness has the Blue and White and a Dark Blue with an orange strip going to the limit switch. The Hi-Lux Blue was attached to the DB/O the red to power and the green ? The toggle switch on the dash had power to the center and the blue went to the blue on the trim solinoid. the green on the toggle went to dead end in the harness plug?:help:

 

[Don S]

Re: Alpha trim wiring.

Well, the harness may be OEM but the control isn't. Here is a wiring diagram of a trim switch with a trailer switch.

View attachment Trim with separate switches .pdf

Don't worry if the connectors, trim pump and fuse holder look different, they are all still wired the same.

EDIT: The trailer switch will bring the drive up, without using the up button.

 

[dozerII]

Re: Alpha trim wiring.

Thanks Don, I think I have it now, you Da Man