No Start, Not Oil Pressure Light, No Neutral Indicator

My bike is a 2006 Bonneville.
So I decided to replace my chrome headlight shell with a gloss black unit. I took off the head light, unmated all of the plugs, then discovered that the puka in the new gloss black shell was just a little bit too small to admit all of the plugs. So I hooked everything back up, and now, with the ignition key in the on position, I have headlight and tail light, but no oil pressure light, no neutral gear indicator light, no turn signals, and the start button does nothing. The kill switch is in the proper position to start. I've checked the fuses, and inspected all of the plug connections in the headlight shell. Everything looks fine.
Any idea where my problem is?

 

I am checking for that. I've got a manual and the wiring is a bit hard to follow. Much water fell out of the plastic sheathing for the harness when I disconnected everything. I've taken the plugs apart (again) and hit the plug fronts and backs with WD40 (this should displace and remaining water). I am an electrical technician by training, but I hate to haul out the VOM and trace the wires if I don't have to. I think that the neutral switch might be a good place to check, but I do not know why I do not have a glowing oil pressure indicator light when I turn on the ignition.

 

Looks like I will have to pull out the VOM. Both the oil pressure light and the neutral indicator get their 12V from the Alarm Control Unit or the Ignition control unit. They are probably under the seat or a side panel. I'll let you know what I find out. Grrr. The weather was great for riding today, that'll teach me to start replacing parts without a clear path to getting on the road again.

 

I have visually inspected the fuses, they all look good. The electrical connections in the headlight shell look good, they lock positively & you can't confuse one connecting plug for another, they won't fit if you try & match up the wrong M/F pair. I will start by tracing the oil pressure light circuit, since the OP light should be on any time the ignition is on, and the engine is not running.

 

I'm getting closer. At the bottom center of the wiring diagram you can see the ignition switch. It makes three connections when on. My problem is that none of the circuits energized by the rightmost connection are working with the ignition on. Everything on the other two connections made by the key switch -- parking & brake light, etc. -- is okay. The 12V for the right most connection passes through a 15A fuse -- the fuse checks okay with a VOM. I have to dig further.

 

Okay, I fixed it.
But I don't know how I fixed it. I checked for 12V power going to and through the ignition key switch contacts to the circuit that was failing, then I disconnected all the harnesses in the headlight shell. I then figured out which connector was which on the wiring diagram, and reconnected them, one at a time, basically building my missing circuit step by step. I reached the point of the last connection up to the dash (still checking for power & ground on the failed oil light pressure indicator), and found that I had 12V and ground going to the oil pressure light. I thought something must have pulled loose on the cable going into the dash. So I hooked up the dash to its connector, and, voila, a miracle, it worked. Everything worked. The bike started and ran perfectly (bad memories of Lucas electrics overwhelmed me).
I think that in the process of disconnecting, cleaning, and reseating the connectors inside the headlight shell I must have eliminated a short caused by the water that had collected inside the plastic sheathing of the cables. Or maybe magic? "Merlin, Merlin, hear my plea! Make my motorcycle go for me!"