86’ K15 starter wiring

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

BJedi76

Full Access Member
Joined
Nov 7, 2019
Posts
152
Reaction score
19
Location
Soldotna, Alaska
First Name
B.J.
Truck Year
1986
Truck Model
GMC Sierra Classic 1500 4x4 SWB
Engine Size
305”
There are three wires attached to my starter.

2 to the large bolt & one to the small bolt.

1) main battery red wire to large bolt
2) smaller red wire (I assume to the ignition switch
3) on the small solenoid bolt (I assume close is the circuit with the ignition switch.)

my question is... is there any reason I cannot hook the number 2 smaller red wire directly to the battery? Why is that wire run under the engine directly to the starter? That seems like unnecessary wire routing. It shouldn’t matter at which end of the main battery wire, that I connect that positive wire.
 

Turbo4whl

Supporting Member
Supporting Member
Joined
Oct 30, 2019
Posts
3,126
Reaction score
7,257
Location
Downingtown, PA
First Name
Wayne
Truck Year
1974
Truck Model
Jimmy
Engine Size
350
The red wire you speak of is a fuseable link that is used to power up everything electrical except the starter. It is not supposed to run under the engine. It should enter a protective metal tube, then head up and over the engine/trans to the firewall.
 

BJedi76

Full Access Member
Joined
Nov 7, 2019
Posts
152
Reaction score
19
Location
Soldotna, Alaska
First Name
B.J.
Truck Year
1986
Truck Model
GMC Sierra Classic 1500 4x4 SWB
Engine Size
305”
Every old GM v8 starter I have ever replaced had these 3 wires connected to the starter.

The really old ones had four wires on the starter.
 

BJedi76

Full Access Member
Joined
Nov 7, 2019
Posts
152
Reaction score
19
Location
Soldotna, Alaska
First Name
B.J.
Truck Year
1986
Truck Model
GMC Sierra Classic 1500 4x4 SWB
Engine Size
305”
So I should put a fusible link from my starter “Batt” bolt to the little junction box thingy on the firewall?

...then power everything else from that box?

...& the purple wire from the small solenoid bolt to the ignition switch?
 

Turbo4whl

Supporting Member
Supporting Member
Joined
Oct 30, 2019
Posts
3,126
Reaction score
7,257
Location
Downingtown, PA
First Name
Wayne
Truck Year
1974
Truck Model
Jimmy
Engine Size
350
Keep in mind the fuseable link was in the metal tube for two reasons. The tube protects it from exhaust heat. Also if the fuseable link burns, it will not, in theory, catch any thing else on fire.

The purple wire runs to the neutral safety switch on the trans, then to the ignition switch. Runs to the clutch switch on a stick shift.
 

pbrstreetgang

Junior Member
Joined
Jul 17, 2022
Posts
9
Reaction score
6
Location
kentucky
First Name
jim
Truck Year
1978
Truck Model
K10 Scottsdale
Engine Size
350
Is there anywhere to source these wires or the harness to replace the originals? If not, how would someone go about re creating these wires?

I’m talking about the two wires that run down to the solenoid - not the main. Battery POS cable
 

Jgonick

Full Access Member
Joined
Jan 12, 2017
Posts
301
Reaction score
379
Location
West Texas
First Name
Joel
Truck Year
1985
Truck Model
K10
Engine Size
350
You can buy fusible links at auto stores or make your own out of fusible wire. (Fusible wire is a special type of wire)

Determine and use the wire size then add the fusible link (4 gage sizes smaller) You can look at the wiring diagrams for your year to see the original wiring sizes. Wire sizes are either metric or AWG (conversion chart attached)

Link to wiring diagrams

example of reading a 78 wire diagram is attached
 

Attachments

  • flink2.png
    flink2.png
    80 KB · Views: 87
  • flink.gif
    flink.gif
    16.5 KB · Views: 97
  • wire_size.png
    wire_size.png
    52.8 KB · Views: 87
  • 78ex.png
    78ex.png
    89.5 KB · Views: 88
Last edited:

Forum statistics

Threads
44,167
Posts
950,747
Members
36,283
Latest member
Cantrell299
Top