Junction block

[Jb77c10]

So I rewired my 77 c10 and neglected to record which wires ran to the junction block under the hood on the firewall. The harness which I installed had no instructions on using this block but I do believe the blower motor and a/C are power through this block, can i supply it with power directly from my battery? Any input would be greatly appreciated

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[bd]

One stud of the firewall junction block connects to the starter solenoid 3/8" battery cable stud (B+) through a 10-gauge red wire and 14-gauge fusible link located at the solenoid end of that wire.  The remaining stud of the junction block connects to a 6" long, 16-gauge fusible link spliced onto the end of a single 12-gauge red wire that then splits into three 12-gauge red wires within the taped harness that separately run to the alternator output post, the #2 terminal of the alternator regulator, and the firewall bulkhead connector.  Both studs of the firewall junction block are jumpered together via a short strap that is integral with one of the connecting wires.

The A/C blower relay has a 10-gauge red wire that connects to the same junction block terminal shared by the 10-gauge red wire running down to the starter solenoid 3/8" battery cable stud.  This B+ connection is used for high blower speed, only.

[Jb77c10]

I rewired the truck with an American autowire kit which had no designation of wires running to the junction block. It basically I believe had purple for nss, red for power to fuse block and I believe one wire to alternator, I will have to check when I'm home. Essentially a wire from the starter + is a constant hot wire is that correct? Theoretically could I power my junction box with a hot wire from my battery as long as it has a visible link?

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[bd]

I rewired the truck with an American autowire kit which had no designation of wires running to the junction block. It basically I believe had purple for nss, red for power to fuse block and I believe one wire to alternator, I will have to check when I'm home. Essentially a wire from the starter + is a constant hot wire is that correct? Theoretically could I power my junction box with a hot wire from my battery as long as it has a visible link?

I have no personal experience with the AAW harness.  AAW may have simplified and streamlined the factory wiring configuration.  Any wire connected directly to the starter battery cable stud is B+.  So, you could substitute a direct connection between the battery positive terminal and the firewall junction block through a suitably gauged and protected wire if you prefer.

[Jb77c10]

Thanks bd, I'm pretty new to this, I had thought about splicing into the main power wire to the fuse block but didn't want to compromise it, idk.

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[Captain Swampy]

Check their website or call them to clarify where to connect it. You could fry your brand new wiring.