Electrical Problem, Dash Not Working

[matthewv3x]

**EDIT: SOLVED** Hey everyone,

I’m hoping to get some advice on a frustrating situation with my 1998 GMC Sonoma. This all started while I was replacing the heater core (which, as many of you know, is already a bit of a nightmare). During the process, I ran into a bigger headache: a ton of spliced wires under the dash that definitely don’t look factory.

From what I’ve read, it seems like these might be leftovers from an aftermarket alarm system or something similar. Unfortunately, things got more complicated when my cousin tried to help. He got frustrated and pulled some of the wires apart before I could figure out where everything was connected—and there are no photos of how it was set up.

Now I’m scratching my head trying to figure out where to even start with this mess. Has anyone here dealt with something like this before? I’d really appreciate advice on:

1. How to figure out what these wires might have been connected to (aftermarket alarms, remote start, etc.).
2. Where I can find a reliable wiring diagram for a 1998 Sonoma to help sort this out.
3. Any tips for safely and effectively cleaning up spliced wiring and returning things to a stock configuration (or close to it).

I’m not super experienced with wiring but willing to take the time to learn and fix this properly. Any help or guidance would mean a lot—thanks in advance!

Photos