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As far as I can tell it's not a sub-harness. It's part of one of the big ones and I think it's the cowl harne$$. This will be a repair. I would not solder without using some sort of mechanical crimps as well.
 
Those are nice Jon. I might even have some at work ;)
But like Dan I like the mechanical connection better. I will probably make a hook termination and sleeve with shrink tubing.


Dan, is the lug that goes to the alternator available?
 
... If the headlights light up, then power is reaching the headlight relay but not the rest of the circuits "downstream" of that, which includes that part of the fuse block powered by the "main" fusible link. If this is the case, then there has to be a break between splice E7 in the engine compartment and the fuse block, and the most likely candidate is the inherent splice on the terminal lug at the alternator.

I agree, well somewhat.:D The headlights are going out with the motor, so my bet would be the harness splice at E6. From looking at the wire pictures, I would open the harness all of the way to the battery and inspect/repair all of the splices, probably would replace the white wire with one size larger to the battery and maybe to the fuse box depending on it's condition.

I hate splices inside of the harness. I would look at ether replacing or pig tailing the smaller wires and bring them all out to connect at the fuse link connector C or to alternator B.
 
Those are nice Jon. I might even have some at work ;)
But like Dan I like the mechanical connection better. I will probably make a hook termination and sleeve with shrink tubing.

Sorry Rory, wrong splice link. These are crimpable, solder, and shrink in one:
Heat shrink, solder sleeve, crimp butt

They also come in rings, spades, and push-on terminals.
 
I looked over the 1997 EWD FSM and many if not all of the symptoms described by beno (post #34) and others can be explained due to a intermittent connection between the two white wires running to terminal "B" on the alternator. Look at page 52 - Power Source - in the EWD manual. +12v runs from the main fusible link on the battery through a couple of splice junctions to the alternator, then from the alternator through another connector to several fuses on the fuse block in the passenger compartment. If there was a bad connection between the two wires at the lug on the alternator, power might not be reliably reaching the fuse block. This would affect the ECU, headlights (because there's no power to the headlight auto off "retainer" circuit), shift lock (because there's no power to the stop light switch), and dash illumination (because there's no power to the tail light relay). This theory is easy to test. Next time the headlights (and, by association, engine) fail, move the headlight switch to the "flash" position (pull the lever towards you). This bypasses the headlight retainer relay. If the headlights light up, then power is reaching the headlight relay but not the rest of the circuits "downstream" of that, which includes that part of the fuse block powered by the "main" fusible link. If this is the case, then there has to be a break between splice E7 in the engine compartment and the fuse block, and the most likely candidate is the inherent splice on the terminal lug at the alternator.



I went to test this theory, but the truck would not start. So I traced the wires the best I could. And the larger wire (possibly 8 gauge) goes directly to the battery. The other looks like it goes to the fuse box. Right now both are cut and unavailable for connection to the alternator.

While we were on the trail we disconnected both of those wires. The wire that feeds directly from the Alt to the battery was simulated by a ten gauge wire directly from battery terminal to alternator. But the other wire was left hanging. The truck would start in this configuration.

What does that mean? Was the fuse box still getting power because the original wires still had contact? When I get the wire I can make some definite connections and hopefully get it started long enough to test Tricky's scenario.
 
I hate splices inside of the harness. I would look at ether replacing or pig tailing the smaller wires and bring them all out to connect at the fuse link connector C or to alternator B.

Rory, I have WeatherPac connectors. Making a subharness is not a bad idea.
 
I went to test this theory, but the truck would not start. So I traced the wires the best I could. And the larger wire (possibly 8 gauge) goes directly to the battery. The other looks like it goes to the fuse box. Right now both are cut and unavailable for connection to the alternator.

While we were on the trail we disconnected both of those wires. The wire that feeds directly from the Alt to the battery was simulated by a ten gauge wire directly from battery terminal to alternator. But the other wire was left hanging. The truck would start in this configuration.

What does that mean? Was the fuse box still getting power because the original wires still had contact? When I get the wire I can make some definite connections and hopefully get it started long enough to test Tricky's scenario.

Yes, your truck was getting power from the original wire that runs from the fusible link through the terminal lug "splice" and then on to the fuse block. But because of the prolonged high temps that splice had experienced, the copper was very oxidized. You can see the conductors are very discolored in your photo #3, indicating oxidation. The oxide acted as an insulator, and thus the splice no longer made for a good electrical connection.

Once you cut the terminal lug off of the original wires, there's no way for power to reach a good number of circuits in the fuse block, hence the inability to start it now. I bet you can still get the headlights to come on though if you move the switch lever to the "flash" position. (Assuming, of course, that the battery is still hooked up.) How about you try this just for fun?
 
Is it still starting for just a few seconds? Does it run longer without the headlights being switched on?
 
For what it's worth... I used to crimp, solder and then use adhesive lined heat shrink on all electrical connections. However I found the repeatability (quality of joint from one connection to another) to be poor (my own fault, I just didn't do it enough to always do get it right). Rarely will you see an OEM (auto or aviation) use solder. Here is what I use now for 90% of my electrical http://www.aeroelectric.com/articles/terminal.pdf. AMP PIDG terminals with a high quality asymetrical crimp tool that is designed specifically for PIDG style terminals. When used correctly this provides a repeatable quality crimp every time and automatically stress relieves the crimp by grabbing the insulation. Weatherpack, MSD Deustch... style connectors provide the same thing (when crimped with the correct jaws - MSD offers a nice tool with interchangable jaws that can do PIDG, weatherpack and their own Deutsch terminals).

Not that you can't make very high quality solder connections (and sometimes you need to), I just find it difficult to do well every time especially when under the hood, behind the dash...
 
I bet you can still get the headlights to come on though if you move the switch lever to the "flash" position. (Assuming, of course, that the battery is still hooked up.) How about you try this just for fun?

No headlights, no flash.

Is it still starting for just a few seconds? Does it run longer without the headlights being switched on?

It wont turn start at all Steve
 
Are you saying that your headlights turn off if you turn off the ignition?

Yes, that was exactly what happened when I tested it last night. However, I was simulating on trail condition, dark, cold, raining, and with driver door opened.

I just went out and tested my '97 and it behaves as I described. Start the truck, turn on headlights, turn off ignition, headlights remain ON, open driver's door, headlights turn OFF.

Yours is different?

-B

I don't think I can say mine is different.
 
Do you have 12v at the headlights?

You should have 12v at the headlight RELAY, but on a '97 you won't have 12v at the headlights proper. This is because the headlights get energized by the headlight "retainer" controller. My FJ62 has 12v to the headlights all the time, but not so with the 80. I'm sure this change happened when the auto off/retainer feature was added.
The headlight relay is energized by one of two things: the retainer controller or by moving the HL switch lever to the flash position.
 
I just read this thread completely. And Although I can't offer any advice, I hope for two things.
1. That Ruadhrigh gets to the bottom of this problem with all the great advice and input on this board.
2. That Beowold updates the trail repair FAQ after this problem gets fixed....afterall, this breakdown did happen on the trail..:D
 
2. That Beowold updates the trail repair FAQ after this problem gets fixed....afterall, this breakdown did happen on the trail..

That's it. I'm changing my UserID to Joe.

-B-
 
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