SImple (for you guys) wiring ?

[Skigirl]

Attached to the firewall in the engine compartment there's what looks to be 2 wiring junctions, one towards the driver's side, the other more toward the pass. side and they are connected by a red wire. On the wiring diagram I have (which I'm studying unto bleeding eye syndrome) I only see one junction box.

My questions:
1) Are both junction boxes?
2) If so, is there some sort of insulation between the junction and the firewall?
3) If not, wouldn't it be grounding to the firewall? It looks like the wires to it are all power, not ground.
4) Is the wire between the "junction boxes" a fusible link?
5) If both are junction boxes, why would there be 2? They're only 18" apart.
6) Am I asking too many questions?.....somebody stop me!!!!!!!! (TIA!)

 

[RaisedK5]

Are you talking about the junction block with the two threaded posts right above the engine, if so its just a plastic block attached to the fire wall, all power, the alternator i believe runs to that block, as for having two, i have two of them, pulled one out of a junker and stuck it on, so i could have another place to hook up the amp and power for the lights, somebody could have done the same before you owned it. If thats the ones you're talking about of course, if not then anybody else got an idea??

Leland aka RaisedK5

"Of all the things I've lost, I think I miss my mind the most!"
"Are the voices in my head bothering you?

 

[HarryH3]

Are these the black plastic things, with a couple of bolt-looking parts right in the center (that the wires attach to)? If so, then they are junction blocks and are indeed insulated from the firewall. Typically, the feeds to the a/c & heater blower, as well as power to the trailer harness, come off of the block on the drivers side. I just went out and looked under the hood of both the '75 K5 and the '90 Suburban. Neither has a block on the passenger side. Either yours has an option that neither of mine have or someone has added the 2nd block.

But in any case, all a junction block is, is a handy spot to pick up 12 volts to run stuff. There are probably some fusible links coming off of at least one of the blocks. They're easy to spot as they are only 6-8 inches long, then are connected to the normal wire for the circuit. There should be some writing along the length of the fusible link, describing its rating.

<font color=black>HarryH3 - '75 K5</font color=black>
<a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
It's a great day to be alive...

 

[Skigirl]

Thanks guys! Leland, yes, there's a threaded post sticking out of them that the wires are attached to. Harry, couldn't tell by looking if they were plastic. Didn't think to clean 'em up to check.

I'm new to the whole truck thing, so still in dufey mode

Obviously then the red wire between them just connects the first to second one. How convenient there are two, what with lights and winches and all arriving soon.

I'll start tracing the wires coming off them against my wiring diagram tomorrow or Monday.

Again, thanks for your time and help!