Wiring problems before inspection

[71C10Guy]

So about a week ago my blinkers, wipers, blower motor, reverse lights, and brake lights all went out at once. I have no explanation for it, but now my alternator only seems to kick on after I use my blinker, which also makes my brake lights go off on whatever side I turned my blinker to. Is there a central fuse for accessories behind the main panel or something? Or any kind of explanation of this all happening at once after a year and a half of the truck being back on the road?
Btw the previous owner had all kinds of aftermarket electronic stuff on the truck that my dad and I ripped out without discretion, so the entire truck is basically just a giant ball of ubconnected and stripped wires. Also what's left of the original wiring harness is spliced into so many times it might as well be a tree. There are splices on top of splices on top of splices on some of the wires. I know this will just take time to sort out or a new wiring harness. My question is possible reasons for multiple systems going out all at once?

[LockDoc]

Originally Posted by 71C10Guy

So about a week ago my blinkers, wipers, blower motor, reverse lights, and brake lights all went out at once. I have no explanation for it, but now my alternator only seems to kick on after I use my blinker, which also makes my brake lights go off on whatever side I turned my blinker to. Is there a central fuse for accessories behind the main panel or something? Or any kind of explanation of this all happening at once after a year and a half of the truck being back on the road?
Btw the previous owner had all kinds of aftermarket electronic stuff on the truck that my dad and I ripped out without discretion, so the entire truck is basically just a giant ball of ubconnected and stripped wires. Also what's left of the original wiring harness is spliced into so many times it might as well be a tree. There are splices on top of splices on top of splices on some of the wires. I know this will just take time to sort out or a new wiring harness. My question is possible reasons for multiple systems going out all at once?

It's really hard telling what is going on with all of the problems you have, and the wiring being messed up like it is. I would just replace the under dash wire loom with a good stock one to start with. It really isn't as hard as it appears and it will give you a clean slate to start with. Just make sure you get one from a truck with the same type instrument cluster you have, and same transmission, & AC/NON AC. Also make sure the fuse holders are not rusted which is common.

LockDoc

[71C10Guy]

Originally Posted by LockDoc

It's really hard telling what is going on with all of the problems you have, and the wiring being messed up like it is. I would just replace the under dash wire loom with a good stock one to start with. It really isn't as hard as it appears and it will give you a clean slate to start with. Just make sure you get one from a truck with the same type instrument cluster you have, and same transmission, AC/NON AC.

LockDoc

Sounds about right. I was really just wondering if there was one fuse that controls the accessories or a circuit or relay, really anything that most of these tie into. Really hoping for a hidden fuse behind the fuse panel? Please?

[kwmech]

Sounds like the majority of the circuits are ignition circuits not battery. Take a look at the back side of the ignition switch plug for melted wires

[bigmac73]

I would just replace the whole harness including g fuse box with new and start fresh , would not want to deal with a electrical fire under the dash while driving

[Andy4639]

The turn signal switch will turn the brake light off on which ever side the turn signal is on. It's controlled by the turn signal switch. This is normal. The alternator coming on isn't though.

Look at the fuses and make sure they all are good and working when power is on. These trucks are bad about the fuses getting rusty and not making contact even in the holders correctly.
As far as the wiring problems that a personal choice.
Here is a link that shows the correct color wiring. You can figure the wires out from here.

http://67-72chevytrucks.com/vboard/s...185856&page=16

[twouvakind]

You already know this but...don't lose your investment to fire.

https://sca.auction/en/21479599-1972-chevrolet-c10

Originally Posted by 71C10Guy

So about a week ago my blinkers, wipers, blower motor, reverse lights, and brake lights all went out at once. I have no explanation for it, but now my alternator only seems to kick on after I use my blinker, which also makes my brake lights go off on whatever side I turned my blinker to. Is there a central fuse for accessories behind the main panel or something? Or any kind of explanation of this all happening at once after a year and a half of the truck being back on the road?
Btw the previous owner had all kinds of aftermarket electronic stuff on the truck that my dad and I ripped out without discretion, so the entire truck is basically just a giant ball of ubconnected and stripped wires. Also what's left of the original wiring harness is spliced into so many times it might as well be a tree. There are splices on top of splices on top of splices on some of the wires. I know this will just take time to sort out or a new wiring harness. My question is possible reasons for multiple systems going out all at once?

[VetteVet]

On the back of the ignition switch is a 12 gauge brown wire that powers all of your accessories. This wire may not be connected any longer (open) to the fuse panel. There is no fuse for this wire or any behind the fuse panel. All the circuits it powers are fused separately.

The wire is pointed out by the black arrows. Notice also that the small tan striped wire that connects with it at the key switch is the exciter wire for the alternator and it is probably open as well. This is probably why your alternator is not charging until you rev up the engine. This is a resistance wire (10 ohms) and is needed to protect the diode trio in the alternator, so you need to get it working.





This is the wire at the fuse panel powering all the fuses for the things that aren't working.

[LockDoc]

Originally Posted by VetteVet

On the back of the ignition switch is a 12 gauge brown wire that powers all of your accessories. This wire may not be connected any longer (open) to the fuse panel. There is no fuse for this wire or any behind the fuse panel. All the circuits it powers are fused separately.

The wire is pointed out by the black arrows. Notice also that the small tan striped wire that connects with it at the key switch is the exciter wire for the alternator and it is probably open as well. This is probably why your alternator is not charging until you rev up the engine. This is a resistance wire (10 ohms) and is needed to protect the diode trio in the alternator, so you need to get it working.

This is the wire at the fuse panel powering all the fuses for the things that aren't working.

If that's the case possibly the ignition switch is bad?

LockDoc

[VetteVet]

That's certainly a possibility and you'll have to tell him how to get it out Doc.

[LockDoc]

Originally Posted by VetteVet

That's certainly a possibility and you'll have to tell him how to get it out Doc.

That's easy enough to do....

67's and some 68's don't have an accessory position, all others do. Just put the key in the ignition and "gently" turn it as far to the left as it will go. Insert a straightened paper clip in the hole (the large ones work best) and push the release pin down (go easy here, it doesn't take much pressure at all) and turn the cylinder to the left a little more. As you turn the cylinder you have to remove the paper clip or it will bind in the hole. The cylinder should pull out. You should not have to force anything.

LockDoc

[Robznob11]

My first thought was ignition switch or brown wire as well. If not that, some fuseboxes have overheated and melted on the back side where all the terminals come together. Since you say its full of splices......I would replace the whole thing. Now if you want a factory fit . American auto wire is good. I chose to go the cheaper route (not quite as easy but very manageable for someone with a little common sense) I used a universal EZ wire 20 circ kit. I have no regrets. Its good quality, but not so plug and play....you have to make your own connections. Now with that said all will require this to an extent.....mine was only like $150 or less for the whole getup.