Guys I am still pretty new to this forum, I have been spending a lot of time reading through threads and such. I recently installed long tubes on my 1975 k5 during this I noticed a few Issues to correct before I start it back up. The wiring was jerry rigged pretty bad to the starter. I looked up the harness guides and trying to use my manual but I am still questioning a few things. what color or what wires should go to the starter/solenoid? i look to have a brown, black and yellow coming from that starter setup to the main firewall wiring block. Are these the three that should go back to run the truck? looks like the previous owners added a red jumper running from the starter to a factory bus bar next to the wire loom holder near the brake booster. Also looks like they had a black wire running from the negative on there down the passenger side to the fuel tank. Any direction with this would be greatly appreciated. I also removed an old red/blue combo wire that was running to the back that was cut anyone know what this would have ran in the original configuration?
CK5
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1975 K5 wiring
- Thread starter Sleblanc
- Start date
This taking a while for me to remember. 12gauge Violet= S terminal on starter solenoid. 10 gauge Red= main terminal on starter solenoid, this is the main power for the vehicle. 18 gauge black also goes to the main terminal-this goes to amp gauge. 18 gauge brown= fuel sender. Yellow wire, I don't think a 75 should have one since it is HEI , but it could go to the "I" terminal of the solenoid. it suppose to supply more power to the ignition circuit during cranking.
But if somebody have been messing around with it, I think you going to have to test for function.
Edit, outside the cab, the wire fuel sender wire should be tan, inside of the cab, it should be pink.
But if somebody have been messing around with it, I think you going to have to test for function.
Edit, outside the cab, the wire fuel sender wire should be tan, inside of the cab, it should be pink.
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Another note the Violet starter wire could soak up oil and turn sort of blackish, but it should be a thick wire.
just cleaned it up looks dark violet now. i took out a red wire they looked to be using as a jumper. what about this wire running down the passenger side it looks black but could have been brown looks to go into the fuel tank. that goes to the sender? so it should go on the solenoid as well?
Interesting, You highlight part of the post and forum gives you the option to add it the multi quote.
Anyway, the only to find out for sure where this mystery wire goes is to see if it goes to the fuel tank. Take note, the fuel tank also have a black ground wire. It usually goes from the sender to frame in front of fuel tank.
At the other end of this wire, you going to have to figure out if black wire is sliced into tan wire.
so the mystery wire is tan and runs down the passenger side to the fuel tank. where should this one go. BTW thank you for the help with this. the wiring diagrams in the book do not explain much. as of now my harness from that main on the fire wall is the violet, black and a tan looking wire. then i have a large red wire running from a power block on the fire wall to the solenoid. i still have a small black that was coming off the solenoid i do not see where it would have went and i have a tan running from the fuel tank that needs connecting.
Tan wire should connect to its mate at the starter harness ( not the solenoid) that runs up the front of the engine and then back across the top of the engine to the firewall harness and on to the junction/feedthru to the cab.
You are hei?
You are hei?
"this one" are you referring the black one going to the fuel tank. It may be an added wire for trailer brakes. Does it goes to the factory junction block? Btw. wires that don't go the factory junction block would the HVAC blower, reverse lights switch on a manual transmission or the kickdown wire on a th400.
yes it is HEI. so it looks like the tan wire was running from down there through the loom to the fire wall . that leaves me with a violet wire and a black wire coming from the fire wall harness junction. they had a heavier red wire running from a junction to the solenoid. looks like that red wire if it is on the junction also tied back to the Alt. i have a black wire coming off the solenoid now that looks like it goes no wheres.
That black wire is to the amp gauge and it goes to the main stud off the starter.
this is the junction box i was refering the large red wire was connected from the solenoid the other red wire ties in with the alt wires. looks as if this was originally spliced together in a different section with a fuse.
Black with white tracer is also for the amp gauge. The two wires measures the amp draw of the red 10 gauge between the starter and and that junction stud. Green is water temp. Dark brown is alternator exciter wire.
Since you have the harness apart, you may have noticed the white wire from the alternator (voltage sense, it is the wire the alternator senses the sense the system voltage and try to charge the system or stop charging. The brown wire turns the alternator on. Red is the charge wire) ties into the red wires to the bulkhead and the charge wire.
Yes
