Electrical Problem

[icanfixall]

My inline fuse continues to blow but only when I start the engine. My main engine wire harness burned most of the end where the power to the glowplug is.so I bypassed that with a much larger cable. then the fuseable link feeding the filter head, the fast idle, the fuel shutoff and the cold advance got burned at the plug so I installed the inline 20 amp fuse. Well that continues to blow on startup. Its the red wire with the yellow tracer. What else does it feed? I suspect it feeds some power to a circuit on the solid state glowplug controller but can't tell for sure. May have to cut the harness cover and look for issues. But would rather know what is fed by this wire. Thanks guys for helping. I'm not very good on electrical issues. Especialy when they happen at random.

 

[franklin2]

If you cut out a fusible link and put a 20 amp fuse in place of it, that can be a problem. Most fusible links are rated very high, and if you want to substitute a fuse, it will have to be a maxi fuse, probably at least 50 amp to hold the same current as the fusible link. Of course it all depends on what size fusible link you cut out. But even the smallest ones are rated for fairly high fault currents.

 

[laserjock]

Franklin is right. If you can find a slow blow you'd be better off. If I remember right, the red/yel wire feeds the vacuum switch and a couple other things. Maybe the headlights?? Is your headlight switch good? I will try to remember to look at my book in the morning. I seem to remember that I had an issue with that same fusible link and figured it out by backfeeding through the vacuum switch plug I think.

 

[icanfixall]

Today I dug deeper into my main engine electrical issue. I continue to need DESPERATELY the wiring diagram for the harness. Seems my issue is the orange wire with the green tracer on it. I figured out why I installed the inline fuse.That part of the engine harness plug melted away as is the case to many plugs. Happens when the power wires feeding the solid state controller gets dirty and heats up.I smoked this probably 10 years ago so I bypassed it. then the orange wire with the green trace fell apart so I installed the inline fuse jumper. No cutting into the harness I find a 20 amp fuse able link up line from my inline fuse. It has a smaller orange wire with a green splice tied into it factory. I removed the passenger side battery chasing the orange wire with green trace but see it goes to another plug.That plug wires go to the ac clutch and the alternator. I suspect this larger of the two orange with green tracer tracer goes to the ignition switch but not sure. I need to look at a wire diagram from under the hood please.

 

[franklin2]

Here's some diagrams.

http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=21150

http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=21139

 

[icanfixall]

Thanks for the electrical diagrams. They really explain much of what I needed.Sad part is no problem found. I really don't know why this inline 20 amp fuse started blowing. Its been on the truck for several years. I did figure out I have an up line fusible 20 amp link so this inline fuse was never needed. I may just remove the inline and depend on the fusible link like oem did. We will see.

 

[franklin2]

Thanks for the electrical diagrams. They really explain much of what I needed.Sad part is no problem found. I really don't know why this inline 20 amp fuse started blowing. Its been on the truck for several years. I did figure out I have an up line fusible 20 amp link so this inline fuse was never needed. I may just remove the inline and depend on the fusible link like oem did. We will see.

Never heard of a 20 amp fusible link. It may be a 20 gauge fusible link, which is going to blow a lot higher than 20 amps. I can't explain why the fuse didn't blow before, but the fusible links are there just to protect the wiring in case some catastrophic happens like a direct short to ground. They usually sit there the whole life of the vehicle and do nothing, and usually blow because someone messes with the wiring, or you are in a accident and cut some wires. They have been known to corrode too.

There is one fusible link inline with the alternator charging wire, and 100% of the time when it's blown, it's because someone is wrenching on or around the alternator and gets a wrench up against the output post on the alternator, or they take the output wire off and let it fall against ground somewhere, without taking the battery loose first.