Re-wired now not starting.

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Joined
Oct 4, 2023
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Location
Rhode Island
Been spending the winter cleaning up the wiring. Cleaned up a bunch of wire in the engine compartment. Before I jumped into the wiring behind the dash I figured I'd make sure the engine started, confirming I put everything back together correctly. Before I did that I was looking at some wiring near the fuse block. There were a set of 7 wires, all butt connected. When I grabbed them to try to trace them, two wires pulled out of the butt connectors. While later I tried to start the truck. I was getting power through the ampmeter, the dial would move when I turned the key from the 1st position to the 2nd. But then nothing. No trying to turn over, no click nothing. Remembered the two wires that fell out of the butt connectors. Jammed them back in the connectors, tried again and the truck started.

Disabled the battery and took a look at the butt connector wires. Looks like someone had created a new wire harness and it seems to go to the light switch and the light that shines on the heater. I haven't tracked it fully but looking quickly, that seems to be where all the wires are going. Was going to order the correct colored wires from @Coolerman and replace the wires the PO ran, so rather than replace the butt connectors I put in an 8 wire plug (only 6 wires going into the plug. Figuring when I get the new wire I can just create a new side to the plug and connect to the factory wire side. Also replaced the 4 wire plug coming from the ignition. The plug itself was falling apart. After all this, tried to start the truck to check everything and its not starting. Power going though the ampmeter. I'm not good with electrical so had a guy at work check the connections and he seems to be getting power on both sides of the wires on the 8 wire plug I created. Also checked the 4 wire ignition wire plug I made. B/Y, W/B, B/R all have power but the black/white is getting nothing. When I created both new plugs, I went 1 wire at a time. would create both sides of the plug, insert into the plug, then cut the next wire, create terminal ends, etc. So I'm pretty confident I have the wires all correct.

Guess I have 2 questions.
1. Why would 1 or 2 of the wires going to the light switch stop the truck from turning over. Truck started right before I started replacing the wiring plugs so I'm leaning towards i screwed something up when I rewired, but for the life of me can't figure it out.
2. What would cause the B/W wire on the ignition to not have power? That wire is going to the starter. I'm pretty sure when we were turning the key the 3 other ignition wires had power but not the B/W wire. I had the starter replaced this summer so I don't think the started is the issue.
 
Well I think its something you did - it worked before you "fixed" it. Check the fuses by actually testing them - they can look good but are bad, maybe you bumped something and blew a fuse.
So did you take pics before when it was working or at least drew a wiring diagram of what was there.

Its like 50 year old wire, twisting and pulling on the harness can cause breaks many feet away. Take plugs apart clean the contacts and inspect the crimp connections, corrosion can crawl under the insulation and ruin the connection even tho it looks good.

When asking for help year/model/market and mods encourages folks to help, if you can't take the trouble to post that, I'm not going to try and look at all of the wiring diagrams to try and figure out the correct one.

Good luck.
 
Ah yes, forgot about that. 1977 FJ40 2F engine. Only mod I can see is a tachometer was added at some point. Also, has a Weber carb with an electronic choke.

All the fuses are good, tested them yesterday. I'm also leaning towards one of my "fixes" being the issue.
 
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So you had 2 PO's connectors pull apart - maybe there are more = pulling and tugging here can effect a wire connection way over there. Look for other in line fuses the PO stuck in. Try using a remote switch to activate the starter.

Switches and stuff do go bad, so maybe its something new, not related to what you did. That's why bypassing things with the remote is a good test. I have to look for my book to see about the ig switch wire - I have no clue where the book is - tough winter.
 
Ahhh, frustrating.

Can you post some pictures? That might help determine what's going on at the fuses.

Since you're trying to start, start at the Ignition Switch.

'77 Ignition Switch should have 4 wires going into a 4 way plug under your column:
  • Black with White tracer (BW)
  • Black with Yellow tracer (BY)
  • White with Blue tracer (WL)
  • Blue with Red tracer (LR)
The BW goes to your starter. When you turn the key to "Start" this wire should be energized at your starter.
The BY goes to the Fuse Panel (to power your Ignition Switched circuits). It's also spliced, and goes to your coil.
The WL goes to your fuse panel (to power your "always on" circuits, such as hazards, brake lights, etc). It's also spliced, and goes to your ammeter, and your alternator.
The LR is goes to your fuse panel, and is for accessory circuits (like the radio).
 
You should find all of the old butt connectors and replace them with heat shrink connectors like these:
heat-crimp.webp
heat-solder.webp


The first are like butt connectors, but have glue lined heat-shrink insulation. You have to be careful that you do not over crimp and damage the insulation. The second are a little trickier to use, but once you know how, they are great. You thread the connector over one of the wires, strip both wires and twist them together, then put the connector over bare copper and use a heat gun to melt the solder and shrink the tubing. You have to be careful to let the solder flow, but not melt the heat-shrink.

Both of these are glue lined, are water, gas, oil-proof, and won't pull apart. These terminal ends are also very good for the same reasons as above:

terminal-crimp.webp


When I'm working on wires in the engine bay, I use the 3:1 or 4:1 glue lined marine-grade heat-shrink over the connectors for added safety. All of these can be found on Amron. Lastly, when I'm repairing a factory terminal connector, I use solder and if there is room, heat-shrink.
 
Thanks, I do use the glue lined heat shrink ones. That's all I used on my sailboat and they worked great so that's all I use now. With the amount of butt connectors I'm finding, I'd probably go through that entire first box of connectors.
 
CloudForestCruise said:
View attachment 4093818
Click to expand...


THis is really poor advice. These connectors fail after only a few years, we have to cut so many out of customers cars who say them on Facebook or instagram adds and rewired their whole car with them

The correct way to splice a wire.. just like Toyota did it on your FJ40 originally and millions of others.
Even better, replace the entire wire terminal to terminal!



open-barrel-wire-splice-454c-05-15mm2-10pcs-pkg.webp
 
cruisermatt said:
THis is really poor advice. These connectors fail after only a few years, we have to cut so many out of customers cars who say them on Facebook or instagram adds and rewired their whole car with them

The correct way to splice a wire.. just like Toyota did it on your FJ40 originally and millions of others.
Even better, replace the entire wire terminal to terminal!



View attachment 4094393
Click to expand...


I second this. When I learned that this was how Toyota did it, I only use these or real uninsulated butt splices, then follow up with heat shrink.
 
nabbasi said:
I second this. When I learned that this was how Toyota did it, I only use these or real uninsulated butt splices, then follow up with heat shrink.
Click to expand...

We only use open barrel for all connections now. It just grips the wire so much much better, and if you think about it is actually more surface area between the wire strands and terminal/splice
 
peesalot said:
I like the pic Matt showed, grabs insulation ( huge plus ) & lets you see the finished contact/condition, good, tight, heat shrink to keep moisture out.
I agree with the fact that butt splices go bad especially in humid climates.
Click to expand...
You can even go a step further and use the shrink wrap that has adhesive in it.
 
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