No tilt and no crank Mercury 40 elpto

[Gadgetmonster]

1997 Tracker Super Guide V16 with Mercury 40 ELPTO - 2 stroke 4 cyl.
I was adding a cigarette lighter outlet that I was going to plug in a USB charger into.
I picked up power under dash from an unused 3 wire harness. Red wire and other wire showed 12 volts so I thought that would be an easy supply of power. When I plugged in the USB charger into the cigarette lighter socket instantly the power tilt motor came on... for about a second then stopped. My guess is now that the harness was there if someone ordered a power tilt/trim control on the dash or something. I removed the wiring I had made to the unused harness and connected to the 12 volt source that powers the live well pump. All good now for the USB.
But now I have lost power tilt up/dn from throttle controller and the up/dn on the motor cowling. Also I have lost engine cranking. Will not attempt to turn over. No click, no sound.
Sounds like a blown fuse to me. So I looked for them. Found only 2. One 20 amp on the side of the motor and one in line attached to the positive terminal on the starting battery. I ohm'd them and both are good and look good.
I have double checked the throttle and am sure it is in the neutral position and I have made sure the emergency kill switch is up in the proper position.
I am pissed at myself for causing this but am extra frustrated that I don't find what's wrong.
Does anyone know of another fuse location?
Is there a way to bypass the neutral switch just to confirm it is not that? Is the neutral switch inside the Quicksilver 3000 control or is it on the linkage on the motor?
Is it the up/dn relays? I find it hard to believe both relays would take a dump at the same time.
Your thoughts please.
Thanks

[Gadgetmonster]

This looks to be a fairly close manual to what I have.
Electrical 2-B-13 has a great troubleshooting guide. I will try this.

http://forum.rentboat.dn.ua/manuals/merc/40_60.pdf

[Gadgetmonster]

Figured it out.
Doing the trouble shooting I found 12 volts everywhere it should be with my volt meter.
Decided to take a heavy jumper from the positive main power wire on the starting solenoid to one of the wires to the tilt/trim pump. Nothing.
Load tested battery. Strong.
Load tested from the positive main power wire on the starting solenoid to ground on the starter... falls to zero.
Despite having the wing nuts hand tight on the battery, the whole problem was minor corrosion on the positive terminal. It carried 12 volts everywhere but would not take any load.
Cleaned the terminals and coated with dielectric grease. All better.
By the way, it does only have just the 2 fuses.