Author Topic: Wiring 101  (Read 355 times)

Offline kjnmontana

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Wiring 101
« on: July 31, 2020, 06:10:25 PM »
Howdy folks, I have a self inflicted wound Iím asking some help on. Background: cleaning up engine bay wiring and failed to take good enough pics to help me return everything back to itís proper place, specifically the stater/ignition system. 1989 V3500 with LE8 454, carbureted, manual. Iím referencing the wiring schematic for R,V and P models (1989) pages 3 and 18. One of the issues Iím having is the wiring diagram does not show how the starter relay is factored into the system.  Iím also struggling with what ties into the junction box on the firewall. And finally, and most embarrassingly, for the life of me, I cannot figure out where to return the 2 red wires coming off the starter solenoid. I see where the battery negative and positive go, but these two heavy gauge wires are a mystery to my simple mind.  Is there a diagram that would take my hand and show the wiring from the pass through block to the distributor, junction box, starter relay, starter and battery, you know something a second grader could follow? Thanks
KJ

Offline VileZambonie

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Re: Wiring 101
« Reply #1 on: July 31, 2020, 06:33:15 PM »
The Battery Positive cable and the two eyelet terminals for the fusible links attach to the same stud on the starter solenoid.
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Offline kjnmontana

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Re: Wiring 101
« Reply #2 on: July 31, 2020, 06:59:46 PM »
Got it, now working back to the relay, junction box, distributor...
KJ

Offline kjnmontana

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Re: Wiring 101
« Reply #3 on: August 01, 2020, 12:48:25 PM »
BD, so where do those 2 wires go to?
KJ

Offline kjnmontana

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Re: Wiring 101
« Reply #4 on: August 01, 2020, 01:46:09 PM »
Ok, itís starting to dawn on me relooking at the wiring schematic, one comes from the junction box and the other from circuit 2 on the engine pass through block, correct?
KJ

Offline bd

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Re: Wiring 101
« Reply #5 on: August 01, 2020, 02:11:58 PM »
Unless someone added one after-the-fact, there is no standalone starter relay.  The ignition switch energizes the starter solenoid directly via the purple wire (Ckt 6).  The two red wires connect to the firewall junction block and the firewall pass-through bulkhead connector (both Ckt 2).  See image.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline kjnmontana

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Re: Wiring 101
« Reply #6 on: August 01, 2020, 04:07:06 PM »
BD, thanks so much for the enlightenment. Another question regarding the fusible links, it shows 2 different gauged wires connected by an incased fuse. Where can I find this style or have they been replaced by the inline fused version and if so, what gauge wire and fuse size is recommended?
KJ

Offline bd

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Re: Wiring 101
« Reply #7 on: August 01, 2020, 07:56:03 PM »
Another question regarding the fusible links, it shows 2 different gauged wires connected by an incased fuse.

What shows this ^^^^ ?  Certainly not the factory schematic I posted.  If you need to replace a fusible link, refer to How to change a Fusible link by VileZambonie.  Read through the entire process before you begin.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline kjnmontana

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Re: Wiring 101
« Reply #8 on: August 01, 2020, 09:50:22 PM »
Thatís how I interpreted the 1989 Wiring Diagrams R-V and P Trucks Models Manual. Page 2 describes the wire annotation as; Wiring Circuit Number, Wire Size as in SG. MM. and Color of Wire. So on Page 18, Circuit 2 wire on the Firewall Bulkhead Connector is a 3.0 Red or a 12AWG Red that is sliced into a 1.0 Red Thermal HW Fusible Link (16 AWG) that is connected to the Starter Solenoid. Iíve read your Fuses and Circuit Protection piece as well as VZís How to Make a Fusible Link. Am I misinterpreting something?
KJ

Offline bd

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Re: Wiring 101
« Reply #9 on: August 01, 2020, 10:21:29 PM »
Thatís how I interpreted the 1989 Wiring Diagrams R-V and P Trucks Models Manual. Page 2 describes the wire annotation as; Wiring Circuit Number, Wire Size as in SG. MM. and Color of Wire. So on Page 18, Circuit 2 wire on the Firewall Bulkhead Connector is a 3.0 Red or a 12AWG Red that is sliced into a 1.0 Red Thermal HW Fusible Link (16 AWG) that is connected to the Starter Solenoid. Iíve read your Fuses and Circuit Protection piece as well as VZís How to Make a Fusible Link. Am I misinterpreting something?

Except for a few typos, this ^^^^ is perfect!   ;)


Another question regarding the fusible links, it shows 2 different gauged wires connected by an incased fuse. Where can I find this style or have they been replaced by the inline fused version and if so, what gauge wire and fuse size is recommended?

However, this ^^^^ is not.  Where do you see an "encased fuse" on the diagram?   ???

Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline kjnmontana

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Re: Wiring 101
« Reply #10 on: August 01, 2020, 10:44:01 PM »
Sorry, that was my attempt at trying to describe what I thought was inside the fusible linkís molded rubber section...what is inside there?
KJ

Offline kjnmontana

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Re: Wiring 101
« Reply #11 on: August 01, 2020, 10:47:26 PM »
I assume itís just heavy protection for where the two wires are connected?
KJ

Offline bd

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Re: Wiring 101
« Reply #12 on: August 01, 2020, 11:18:50 PM »
I think you are referring to the molded urethane encasement that completely encloses and seals the parallel splice that joins the two wires together end-to-end.  When it becomes necessary to replace the fusible link, that splice with its urethane encasement is severed from the wire bus.  A new 6" long fusible link of the appropriate gauge is then crimped and soldered onto the end of the wire bus.  Finally, the splice is entombed in marine grade, adhesive lined, dual-wall polyolefin heat shrink.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline kjnmontana

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Re: Wiring 101
« Reply #13 on: August 02, 2020, 08:45:09 AM »
Thanks, the education continues!
KJ

Offline kjnmontana

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Re: Wiring 101
« Reply #14 on: August 02, 2020, 08:10:33 PM »
BD, Iím cleaning up the oil pressure sensor (OPS) wiring and once again trying to interpret the proper wiring diagram for my 1989 V3500, carbureted 454 manual tranny.  I have a Holley 4BC with electric choke with a single ~18 AWG wire (not sure where it is suppose tie into), and the OPS with a single ~18 AWG Tan wire going to circuit 31 on the Firewall Bulkhead Connector and two wires (~ 18 AWG) coming from what I assume is the electric choke OPS.  The electric choke OPS is attached to the OPS just below the oil filter. One of the wires from the electric choke OPS is connected to circuit 39 on the Firewall Bulkhead Connector which I believe is the Hot in Run and Start Fuse. Not sure where the second wire goes...Thanks.
KJ