Fuse panel ID large connector near the fuse box?

Is there anything to interupt power supply to heat/air control on 92 chevy 1500 other than the 25 amp fuse in the fuse panel? I have replaced the 25 amp fuse and tried 3 used control modules but none of those show that they are recieving power. None of the control units will even light up much less run the blower.

My headlights work, but my taillights do not and neither do my dash lights, but all of my other electrical systems are just fine including brake lights, backup lights, turn signals, interior lights, radio, power windows and locks and heater/ac. We have checked all of the fuses in the box under the steering wheel and they are all fine. Is there another location under the hood of fuses that we can check or do you have any ideas of why I am having this problem? It just started all of a sudden today.

I have a no start issue, truck cracks fine, has spark, but the fuel injectors are not getting power, I have been having an issue figuring it out and the location of fuses and relays.

Where is the A/C Heater fuse located?

I have the truck listed above half ton. One morning when I went to go start my truck I turn my key the starter engaged engine started then all the sudden it shuts off and smoke was coming out of underneath my hood. When I want to go check it out the power distribution block wires were shorting out and one of the red inline fuse from the power block caught on fire ! The power wire that got caught on fire is the one that runs to my convenience block it's a thick red wire. My question is, that the wire that goes to my ignition switch? I ended up cutting that red wire from the power junction block and I check continuity from the wire. I cut to a ground and it showed that there was continuity when it's supposed to be a power source from the junction block. Does that mean I have a short to the frame before it gets to the ignition switch? I really don't have any idea.

This red wire on power block was the one that actually literally caught on fire! Luckily I put it out before it got out of control. There was a inline fuse that I cut out that red wire. Now I put a continuity tester probe on that red wire that was shorting out that I had cut out from the power junction block (the red wire in this picture that runs to the steering column) and the other end of the probe to a ground on the firewall and the probe showed there was continuity from the ground to the that red wire. Now my question, is there supposed to be continuity or does that mean that there is a short along that wire to ground somewhere? I hope I make sense to you.

What are these symbols on diagram?

The symbols where the red wire goes through.

Yes I have a 1988 chevy silverado c1500 and my headlights taillights and dome light quit and do not have any power coming out of the fuse box what might the problem be?