Pete 386 electrical schematics? (2024)

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..

Supermiller – Class 8 Trucks Wait for page to load completely. Right side of page.

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

Well looks like you are going to need the "pro" when it comes to anything Peterbilt. Post the last 8 vin# of one of those 386 you have and hopefully spsauerland will see this and help you out.

Have you compared the wiring diagrams on Supermiller to what you've got?

I doubt they made a completely unique wiring harness for the 386. There has to be some crossover with other trucks

@pushbroom is the pro with red ovals, I prefer to work on the world's best! Last six of VIN and which diagrams you looking for?

386s are the same wiring as 389/388. The supermiller 389 diagrams are good enough unless you have a specific issue you are trying to track down.
@spsauerland still waiting for you to ditch the kws and join the winning team!

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 ??

The power for the backup lights come from a 20amp fuse in the cab labeled engine accessory. It then goes out the bottom firewall connector to the trans switch. It then comes out the other side of the switch and goes directly to the reverse lights.
The backup alarm is slightly different, it tees into the power leaving the reverse switch and sends it to the chassis node to trip an internal relay to send power from the G8 fuse under the hood to the backup alarm.

So at the orange wire on the trans are you getting 12V? Will it light up the reverse light it you hook it up there? I suspect you are barely getting enough voltage at the trans switch which is why it cannot light up the bulb but can just signal the chassis node to briefly turn on the backup alarm.

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 ....