93 C1500 Junction block question
 

On this 93 C1500 project I am working on the heavy black wire with the arrow pointing at it is just cut off at the other end and I am not sure where it goes.

Thanks

https://i.ibb.co/VWDwD7B/IMG-20210719-152308-r.jpg

Re: 93 C1500 Junction block question
 

The schematic for the junction block in the service manual did not match the way these trucks came from the factory before anybody touched them.

That position on the block was usually used for optional equipment like an under hood light or an auxiliary cooling fan.

Re: 93 C1500 Junction block question
 

I think it's the feed for 12v to the junction block, I don't see where it is getting 12v from any other connections.

Only connection from the battery I know for certain that has 12v is the cable to the starter. Other than that I can't see where the rest of the truck is getting 12v to anything.

Re: 93 C1500 Junction block question
 

The schematic shows a wire running from the positive battery to the battery junction block. It also shows a wire from the alternator out put terminal going to the battery junction block.

The schematic shows all wires connected to the battery junction block have a fusible link.

Re: 93 C1500 Junction block question
 

On my '93 that went to the starter. I moved it to the battery.

Re: 93 C1500 Junction block question
 

Thanks! That's how I ran it and didn't burn the truck down.
She runs again.

Re: 93 C1500 Junction block question
 

Do you happen to remember if your 93 had 2 oxygen sensors?
I am seeing references to 2, one in the left side exhaust manifold and another down under the cab.
I can only find wiring for the one under the cab ( 3-wire connection)

Re: 93 C1500 Junction block question
 

There is only one oxygen sensor and it has one wire.

Re: 93 C1500 Junction block question
 

I can't find a one wire hookup for a oxy sensor anywhere.

This truck originally had a 4.3v6 and was swapped to a 350, wonder if that has something to do with it.

Re: 93 C1500 Junction block question
 

It has everything to do with it.

The trucks with a 4.3 V6 had a three wire heated oxygen sensor. The trucks with a V8 had a one wire oxygen sensor.

Re: 93 C1500 Junction block question
 

I ordered the 3 wire sensor, see how it runs, if runs decent I will leave it be.
If not I will see if I can hunt down a 93 V-8 engine harness.