Pete 386 electrical schematics?

we have about 6 386 trucks in our fleet, dont have electrical schematics for anything.. where can i find schematics for a 386? ive seen 389,379, etc. etc. etc.
Tired of chasing hopes and beating my head against the wall trying to fix even seemingly simple issues..

 

i followed this and it brings up all kinds of information for 379, 389, newer models, etc. i see nothing for a 386.

 

I ended up finding a reliable schematic but now have run into a stand still...

2012 Pete 386.
Have no power going back to reverse lights.
I and have continuity from reverse light pin in rear bumper to backup switch on trans and at chassis node pin. No power.
I found a rubbed wire for the orange wire going to backup switch on trans, thought that would fix it but no luck.
Weird part is, when I plug in the connection at the back bumper partly the alarm will sound, but plug it in all the way and it kills it. Seemingly my alarm is getting power from the tail lights which doesn't make any sense seeing as it should come from reverse lights. HELP ??

 

thanks everybody, sorry for the long delay in replies. kinda have shotty connection out in the shop and ive been going on a couple different trucks. i had the wiring all laid out and got frustrated and walked away, at the end of the day i put it all back together to get him back on the road and it works now... i fixed a gang of wires for the chassis harness where it goes under the cab and a loose connection up by the trans switch and it started working.i am assuming the connection by the switch had to be the problem after i fixed the broken wires. @pushbroom thanks for the help and info. though now ive got another truck washer pump not working thats giving me a headache.. these pete's ....