Took the boat out the first time after many upgrades and the trim on the throttle and dash isn't working to trim the drives without pushing the "trailer" button as well so I'm guessing it's something to do with the trim limit switches which durring my upgrades I only removed the transom assembly not the trim limit switches so not sure why they would have went bad. Anyone got any ideas?

We had an alpha one drive that would occasionally do this where the up trim button would not work but the down one would work and the trailer button would work. For us it was loose wires on the trim puck mounted on the inside of the outer transom assembly.

make sure you have all the wires pushed togeather,don,t ask me how i know this

Thanks I will double check this as alot of things have gotten pulled on and tugged on while doing this project could be just a simple wire is disconnected...Hopefully it's not the trim limit switches.

I'm a little confussed here.Are you actually calling the Drive the Transom assembly? You would have to remove the limit switchs if you removed the transom assembly. If you removed the limit switchs off the gimble ring than unless you put them back on in the exact same spot they may be out of adjustment. Have someone hold the trim switch in the up position while with the limit switch loosened turn it in the screw slots and see if it kicks on when it hits the right spot. They should be adjusted so the drive stops rising when the flat surfaces on the drive are about to come out of the guides on the gimble ring.

No I removed the entire transom assembly off the boat to install Imco Extension boxes then just bolted it back onto the box. I never touched the trim limit switches. If the wires are hooked up correctly then I'm guessing they went back moving them around or just time to change them..I'm guessing they are original equipment.

Well I found the problem and now I need some help fixing it...I didn't have the trim limit switches hooked up. Reason for this is I'm guessing on 500efi's they aren't used because of the HP Transom Assemblies. I have a 500efi manual and it says that the "UP TRIM" is a light blue with white line/white wire. Does anyone know where these would be in the harness? I'm guessing the harnesses from the 10pin are same for most boats.

I dont think its in the pin harness at all. ?!
there should be wires coming out under the throttle, just connect them to the trimswitch in the dash and u should be fine !
blue up/green down/red power !!!!!!!!
then follow the wires to the pump, they also have a fuse in them ! it has nothing to do with the plug of the engine.

Well it has to have wires coming from the dash to the engine area. I have all that wired already as my 496's had it, but I can't find where it was plugged in so I'm guessing it was in the harness coming to the engine.

Look along the gunwales on both sides of the boat for 2 strand wires that are probably black in color and disconnected. The trim limit switches come out of the transom assembly and then are spliced to what looks like a black lamp cord or speaker wire and that is what feeds back to the trim switches. On mine there was one run up each side but some boats will take them both down one side. If you are confident in your abilities as a "Master Trimmer" you can just splice the two strands together which will bypass the limit switches completely,