Where does the black wire with an inline fuse go? 1973 blazer

[73blazer73]

so I bought this blazer cheap and the PO had cut the wiring harness completely off just past the alternator and scabbed in a push button start to the starter. I ripped all the scabbed in wires out that were all over the vehicle and left it with basic wiring. So far I think I've got it figured out but I have no idea where the black wire goes. It comes from the firewall where all the other wires come out and just past the firewall it has an inline fuse in it. I checked it with my voltmeter and it's hot all the time with the same voltage as the battery. It ran the full length of the harness all the way past the alternator where it was then cut. The rest of the wires are as such....

Red- to battery positive, Came from junction on firewall

Purple- to starter

Yellow- to starter, Came from coil

Brown or tan- I think it goes to fuel sender

Black- (fill in the blank please)

She fires right up, gets about 14+ volts on the battery while running and has no drain on the battery. Lights work. I don't know where that wire goes.

Any input would be highly appreciated. Thank you.

 

[Russell]

Can you show us a picture of the wire where it comes out of the firewall? Also, what year is the truck?

 

[campfire]

Can you show us a picture of the wire where it comes out of the firewall? Also, what year is the truck?

This. Where does it head after going through the firewall? More pics would help make this clearer.

 

[73blazer73]

It leaves the firewall goes behind the master cylinder and heads over to the passenger side valve cover. Runs along the valve cover and down past the alternator and that's where the whole wiring harness was cut.

 

[pblaze725]

I think it may be for an electric choke.

 

[6872xtc]

I am assuming from your username that you have a '73, which would have an ammeter. Now I don't know that year wiring well, but my '72 and older trucks have fuses protecting a shunt wire that only goes through the ammeter. This was so that the charge current didn't go into the cab.
I am guessing that you have the same situation here, as with my '72, that wire is black. The '72 Has 2 fuses for the shunt circuit. It used 2 amp fuses. The system will still charge even with a blown fuse, it just won't have a working ammeter.