Fusible Link?

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.

SASKCHEYENNE75

Full Access Member
Joined
Jan 11, 2021
Posts
95
Reaction score
118
Location
Saskatchewan, Canada
First Name
Jarod
Truck Year
1975
Truck Model
C10
Engine Size
350 4bbl
Good afternoon,
I have no power to my headlight switch. I removed the switch and tested the contacts to make sure the switch is working properly and it is.
Next I checked for constant 12v power at the red wire in the headlight switch harness and there is none.
I disconnected the 3 wires from my starter and pulled them up to the top of the engine for easier inspection.

The thicker of the two smallest wires has this connector at the end. Is this the fusible link? I probably shouldn't have cut it off because now I have to replace it for sure. I just want to be sure I'm putting the same thing back on
 

Attachments

  • 20240402_143640.jpg
    20240402_143640.jpg
    143 KB · Views: 65
  • 20240402_143644.jpg
    20240402_143644.jpg
    110.9 KB · Views: 65

Jgonick

Full Access Member
Joined
Jan 12, 2017
Posts
298
Reaction score
377
Location
West Texas
First Name
Joel
Truck Year
1985
Truck Model
K10
Engine Size
350
yes- that's a fusible link.

Fusible links are usually 4 gauge sizes smaller than wire it is protecting.
You can buy them at an auto part store or make your own out of fusible wire-
 

Attachments

  • wire_size.png
    wire_size.png
    52.8 KB · Views: 51
  • 86.jpg
    86.jpg
    98.7 KB · Views: 55
Last edited:

SASKCHEYENNE75

Full Access Member
Joined
Jan 11, 2021
Posts
95
Reaction score
118
Location
Saskatchewan, Canada
First Name
Jarod
Truck Year
1975
Truck Model
C10
Engine Size
350 4bbl
1986 Chev K30
Now I'm left with these two wires that go to the starter along with the big battery cable. I'll replace the end of the smaller wire too likely. Does that need a fusible link too?
yes- that's a fusible link.

Fusible links are usually 4 gauge sizes smaller than wire it is protecting.
You can buy them at an auto part store or make your own out of fusible wire-
So both of these wires need a fusible link?
You must be registered for see images attach
 

Jgonick

Full Access Member
Joined
Jan 12, 2017
Posts
298
Reaction score
377
Location
West Texas
First Name
Joel
Truck Year
1985
Truck Model
K10
Engine Size
350
both red wires -all hooked to the same terminal- I would say yes. The diagram I attached is the typical wiring of an 86.
 

Attachments

  • 86.jpg
    86.jpg
    124.8 KB · Views: 62
Last edited:

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,266
Reaction score
2,206
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
I used a TS-6 sending unit on my ‘75 and it is a pretty close match to proper temperature reading. The correct ‘75 vintage GM sending unit is only available as NOS, so it’s usually expensive. My gauge has no numbers, but fully warmed up to about 185 degrees it shows between 3/8 and 1/2 with the TS6. The TS6 also has the correct “button” connection for my original wiring.
 

BadBowtie

Full Access Member
Joined
Mar 4, 2023
Posts
185
Reaction score
224
Location
North Texas
First Name
Jon
Truck Year
1984
Truck Model
Chevrolet
Engine Size
5.0L
Check the fuseable link up on the firewall too. Between the power brake booster and distributor.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Good afternoon,
I have no power to my headlight switch. I removed the switch and tested the contacts to make sure the switch is working properly and it is.
Next I checked for constant 12v power at the red wire in the headlight switch harness and there is none.
I disconnected the 3 wires from my starter and pulled them up to the top of the engine for easier inspection.

The thicker of the two smallest wires has this connector at the end. Is this the fusible link? I probably shouldn't have cut it off because now I have to replace it for sure. I just want to be sure I'm putting the same thing back on
If it is only the headlight switch... it isn't a fusible link problem. Did you check the headlight fuse in the fuse box?
 

SASKCHEYENNE75

Full Access Member
Joined
Jan 11, 2021
Posts
95
Reaction score
118
Location
Saskatchewan, Canada
First Name
Jarod
Truck Year
1975
Truck Model
C10
Engine Size
350 4bbl
If it is only the headlight switch... it isn't a fusible link problem. Did you check the headlight fuse in the fuse box?
Yep the headlight switch was the first thing I checked and its operating as it should. As it turns out it was my fusible link near the starter. Replaced that and I'm back in business!
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,439
Reaction score
5,581
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Yep the headlight switch was the first thing I checked and its operating as it should. As it turns out it was my fusible link near the starter. Replaced that and I'm back in business!
Interesting... you should have had a bunch of other inoperative stuff too then.
 

Forum statistics

Threads
44,163
Posts
950,684
Members
36,276
Latest member
2manysquares2care
Top