Electrical failure.
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Electrical failure.
Hi again all,I had an interesting if a little inconvenient incident last night.Iwas turning the rig around in my yard to put the attached boat away and got nicely across the driveway and suddenly and catastrophically lost all power.Everything completely dead accompanied by burning smell..Checked under hood and found one of the wires from the starter relay to somewhere,presumably the ignition switch circuit,had burned through. Now,I know that if a wire burns through it is for a good reason,namely a dead short somewhere.My big problem is finding that somewhere. Testing revealed there was no juice getting to the ignition switch via the two yellow feeds into it.I need to know which wire from the starter relay is the main feed.There are three coming off it besides the main Batt leads and the red and blue ignition wire but my manual only shows one wire. If there are any electrical wizards among you who can throw any light on this I'm grateful in advance.I ran a jury jumper from the relay to my starter button to get the rig going but that's all it will do.Everything else except the radio(don't ask) is dead.
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From: Angier, NC
That wire that burned up would most likely be a fuse link.
The out side of the fuse link wire is soft rubber type where normal wire is more hard.
If you replace that link wire, you can get them from auto parts stores, you should get power back inside the truck.
Now the $64 question why did it "pop"?
You might want to get a circuit breaker and wire it in place for testing till you find the short.
Dave ----
The out side of the fuse link wire is soft rubber type where normal wire is more hard.
If you replace that link wire, you can get them from auto parts stores, you should get power back inside the truck.
Now the $64 question why did it "pop"?
You might want to get a circuit breaker and wire it in place for testing till you find the short.
Dave ----
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From: Virginia
What you can do is take the battery cables off the battery, and put a small 10 amp battery charger on the large battery cables to take the place of the battery. That way if there is a problem, the battery charger circuit breaker will trip and not burn any wiring up. It will not crank the starter over, but it should run everything else in the truck.
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From: Virginia
Here is a link and on page 14 it shows up to 3 possible wires in that location on the large battery lug on the solenoid.
Charge & Power Distribution - Gary's Garagemahal (the Bullnose bible)
If you have a ammeter in 1981 you could have up to 7 wires in that location (page 12).
Charge & Power Distribution - Gary's Garagemahal (the Bullnose bible)
If you have a ammeter in 1981 you could have up to 7 wires in that location (page 12).
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Thanks Fuzzface,you are right it had the softer rubber outer as you say so I can renew that .However it doesnt do any good if it immediately burns out again.Forgive my ignorance but what exactly do you mean by a circuit breaker,is this a piece of kit you can buy?
Franklin,I tried the battery charger trick an it immediately broke the circuit so I know it's something connected to that wire,but what? I tried the Gary's Garage site but I could not open it so no joy there.What puzzles me is that I can find no reference to a chargeing wire from the alternator on my wiring diagram,nor any feed to the fuse box.
Franklin,I tried the battery charger trick an it immediately broke the circuit so I know it's something connected to that wire,but what? I tried the Gary's Garage site but I could not open it so no joy there.What puzzles me is that I can find no reference to a chargeing wire from the alternator on my wiring diagram,nor any feed to the fuse box.
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From: Virginia
Here's the continuation of the above diagram. You can see how it hits the ignition switch and the fuse box
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+Thanks Franklin,I'm no genius with wiring diagrams but the more I look at these the clearer they become.It will give me something to think about for a few hours.
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From: Angier, NC
Thanks Fuzzface,you are right it had the softer rubber outer as you say so I can renew that .However it doesnt do any good if it immediately burns out again.Forgive my ignorance but what exactly do you mean by a circuit breaker,is this a piece of kit you can buy?
Franklin,I tried the battery charger trick an it immediately broke the circuit so I know it's something connected to that wire,but what? I tried the Gary's Garage site but I could not open it so no joy there.What puzzles me is that I can find no reference to a chargeing wire from the alternator on my wiring diagram,nor any feed to the fuse box.
Franklin,I tried the battery charger trick an it immediately broke the circuit so I know it's something connected to that wire,but what? I tried the Gary's Garage site but I could not open it so no joy there.What puzzles me is that I can find no reference to a chargeing wire from the alternator on my wiring diagram,nor any feed to the fuse box.
You should be able to find one at the parts store, little silver box thing with 2 spade connectors.
You may need to rig up something to hook it to what is left of the fuse link wire for testing.
Dave ----
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From: Virginia
Fuse link J is your main power fusible link that powers the whole truck. That hooks to the large battery terminal on the starter relay (solenoid). The dotted lines above that hook in the same place, but being dotted means they are options you may or may not have.
S202 is a main splice for your alternator output. Current from that point will go 3 different directions, depending on if the battery is charging, or something is hogging all the power in the truck and most of the alternator current is going to the left side of the diagram.
Guess what? I see a mistake in this factory diagram. The wire going from splice S201 down to the A terminal on the regulator should be the yellow/white wire. The large output wire coming off of the B terminal of the alternator going to splice S202 should be the black/orange wire. Things like this really mess up newbies trying to fix their trucks. Believe it or not, you run into this all the time with Ford documentation
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