2000 SAN wiring - PME / Accessories wire

[msquito]

Hey all, running into some user-error caused electrical issues in our 2000 SAN. I seem to have killed my accessories wire, and fearing the issue may be internal to the PME. I am reworking our ballast system, and have wired up a series of switches and relays to control motorized ball-valves and reversible pump. Instead of patiently connecting the switches one at a time and minimizing at-play variables, I got excited, hooked everything up, and flipped the switch. Pump fired up, which caught me by surprise because I thought the 2-way rocker was in neutral/off, I reactively hit the switch (don't recall if it actually was in off, or if I moved it to off, or what), and the pump went quiet and the accessories wire appears to be dead.

I had tied my switches into the red accessories wire just upstream of the stereo in the console, and expected (though foolishly didn't confirm) there was an upstream fuse. In the end, it appears the accessories wire comes out of the PME, forks to the dash and the console, and when the PO installed an aftermarket head-unit in the console, the fuse did not make it back into the mix. So, I've gotten a multi-meter on things, and it appears that the accessories wire coming out of the 40-pin connector on the PME is dead. All other wires seem fine, everything works except for stereo, and the 12v cigarette lighters on the dash and the console (everything fed by the red accessories wire). I was hopeful I'd find a blown fuse somewhere in-line, but no such luck. There have been a number of *modifications to the factory wiring I'm realizing and all three fuses upstream of console stereo in the console wiring diagram are missing.

I've removed all of my switches to try and just get back to previous working state so I can now be smart with my switching installation/validation but at a loss with the accessories wire. My impression is that the PME isn't user-serviceable, and if I've shorted the accessories wire within the PME as I suspect - now what? I suppose I could wire up a relay off of the yellow constant power wire but if there's any hope of salvaging factory gear, that'd be my preference. Any thoughts?
thx!

[msquito]

quick update - having +/- traced this back to the PME where I was having problems, I decided to ignore the "Not user serviceable / DO NOT OPEN" sticker and crack that beast open to see if I had melted any wires or anything obvious in there. Some learnings:

• Opening the PME was less scary than the sticker made it seem (I was sure to carefully remove all wiring feeds before I did - note: I'm not recommending anyone else open it up, I don't think it's necessary TBH and it probably voids some warranty for those who are still within one).
• There's no wiring within the PME, it's all components on a board.
• There are a series of circuit-protecting modules (with the buttons) that plug into a double-blade interface. The button on these things doesn't stick out really far when tripped - there was one which was popped (UNLOCK, top-left), the button sticks out less than 1/4" when popped.
• The red accessories wire, while as I understand it is typically referred to as the "accessories" wire in 12V applications, does not correspond with the ACC circuit on the PME - my guess it it is tied to that UNLOCK ckt

So, after opening that up, unseating, cleaning, and reseating all of the ckt breakers, I carefully put it back together, reconnected the 40-wire block then neg/pos leads and red wire was back in business. (I expect, had I been more diligent in investigating all of the breaker-buttons before taking it apart I would've found the UNLOCK had tripped, pushed it in and been in business, but my brain kept tying the red "accessories" wire to the ACC ckt so I didn't explore the outside of the box as well as I probably should've. Some photos to go with descriptions attached.
cheers!

[Scooter G]

Nice work!
I think most of us have torn something apart before in the heat of the battle, and it turned out to be an external problem.
My demise started when I was 3 years old, I just couldn't put stuff back together at that point, or so says my Mother.

[msquito]

yeah, I'm kinda the same - have definitely taken things apart enough to know that sometimes I've wished I hadn't... I was semi-concerned that when I pulled the face off of this thing there'd be a ton of spring-loaded components that I'd never get back into place but was pleasantly surprised that the whole thing was pretty painless if not pointless...