Mark80K15
Full Access Member
- Joined
- Apr 18, 2021
- Posts
- 118
- Reaction score
- 83
- Location
- Sicamous, BC
- First Name
- Mark
- Truck Year
- 1980
- Truck Model
- K15
- Engine Size
- 350
Hello, 1980 GMC K15 350 4-bbl, aftermarket Sun tach. There is a wiring harness that plugs into the HEI 12V/tach port. Can you please tell me what this harness is?
The 1st picture shows a 12V orange wire (power for distributor) with a male white plastic terminal and white tach wire with a spade connector. They can reach and fit in the HEI 12V/tach port, but they are not plugged into that port. Instead, they are plugged into a female plug which is the beginning of the harness.
The 2nd picture shows that same female plug at the beginning of the harness, and emerging from it, a thick orange wire and smaller white wire go to a black male plug. That black male plug also has an orange wire and white wire exiting it, and that black male plug is what plugs into the distributor now.
In the 3rd picture, and from the black male plug, the orange wire has a white cylinder (fuse?), and it and the white wire proceed into the rest of the harness. At one point the harness splits into 2. At one end is a silver block, and at the other end is another black male plug. There is also a black ground wire coming out of the harness. None of these 3 ends (silver block, another black male plug, black ground wire) are attached to anything, and the engine runs fine.
The 4th picture shows a little more detail of the silver block.
The engine used to have a 4 bbl Rochester carb, now it has a Holley. For some reason I think this harness might have something to do with the original carb.
Can anyone please help and tell me about this harness? is this an Electronic Spark Control?
The 1st picture shows a 12V orange wire (power for distributor) with a male white plastic terminal and white tach wire with a spade connector. They can reach and fit in the HEI 12V/tach port, but they are not plugged into that port. Instead, they are plugged into a female plug which is the beginning of the harness.
The 2nd picture shows that same female plug at the beginning of the harness, and emerging from it, a thick orange wire and smaller white wire go to a black male plug. That black male plug also has an orange wire and white wire exiting it, and that black male plug is what plugs into the distributor now.
In the 3rd picture, and from the black male plug, the orange wire has a white cylinder (fuse?), and it and the white wire proceed into the rest of the harness. At one point the harness splits into 2. At one end is a silver block, and at the other end is another black male plug. There is also a black ground wire coming out of the harness. None of these 3 ends (silver block, another black male plug, black ground wire) are attached to anything, and the engine runs fine.
The 4th picture shows a little more detail of the silver block.
The engine used to have a 4 bbl Rochester carb, now it has a Holley. For some reason I think this harness might have something to do with the original carb.
Can anyone please help and tell me about this harness? is this an Electronic Spark Control?
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