Last night I did a stupid thing.
I was checking the timing on my 68 as it has cooling issues. I hooked up my timing light, neg to the ground on the alt, and pos to the pos of the alt. Right before hooking up on the #1 plug one of the clip leads shorted and the car just died. I have no power, no interior lights, nothing dead. It was late and should have been working on it anyway so i did not check the fuse panel , any other idea's if the fuses check good where to start after that?

Thanks
Denny

 

I have a 1969 wiring diagram which may be different. it shows 2 factory inline fusible links going from the alt. to the horn relay. They may be burned. One of the links is on a Orange wire and supplies voltage to the fuse block.
Rookie guess.....No voltage at the horn relay means 1 or both links are burned.

 

I will check mine out when i get home from work. TY

 

As mentioned above, sounds like the fusible links (s) did their job. Check with a multimeter. You can get replacements at NAPA. They will not be stock appearing, but they will work. Jerry

 

I agree with Doorgunner.
If you have no power at all, it is most likely one or both fusible links have blown. If it is, in fact, the fusible links, they are sized two wire gauge sizes smaller than the wire they protect. Example: #10 AWG uses a #14 AWG fusible link. Do not oversize a fusible link it's there to protect to the wiring system, just like it did for you.

 

Thank you

 

Will the gage be on the wire?
I figured i would test them when i get home tonight from work and see.
I see in my manual:
Batt spliced at the solenoid14gage
Horn /black white 16 gage
Molded spliced to regulator 20 gage orange
molded ammeter circuit 20gage

 

My two cents, disconnect the battery, I did like a lot of guys and installed a quick disconnect switch, now may be a good time to add one.

 

Fusible links are NOT regular wire. You do not want to substitute regular wire for a fusible link...unless you really understand them. THEY will fry and NOT start an insulation fire...or transfer the excessive heat to somewhere else in the wiring.
Use the right product to replace a fried fusible link.
P.S. Whatever link(s) fried, they did their job---protect the wiring from the "mechanic" when creating a dead-short in the wiring...

 

I want to use the right product to replace a fried fusible link. Any place make reproduction fusible links?
My local NAPA closed down, just have AZ and O'R.
Silly question could a inline fuse be used?

 

No the Ga. size will not be on the wire. I assume you are quoting fusible link sizes, you are correct. The fusible link may have the Ga. size on it.

And no you can't use inline fuses to replace a fusible link. They will blow too fast and every time one blows, you will have to replace it. Fusible links are more robust than fuses, they can handle higher spikes in current whereas a fuse cannot. Don't try to re-engineer the wiring system, Gm has been doing this for a long time, it's tried and true.

 

Okay i get it now,,Thank you for clearing the ga sizing up for me.
So to fix the blown fusible links, replace the wire that is indicated in the pic. Do those black barrels open? so you can make the connection to the fusible link wire.

 

My AZ or O'R does not carry the link wire but NAPA does. I'd just go to their closest location to you.
https://www.napaonline.com/en/search...ink&referer=v2

 

No those barrels do not open up, they are sealed units. I think they (barrels) are the connection between the actual wire and the fusible link. Yes replace wires shown in pic. Did you notice the reduction in gauge size, the thinner wire is the fusible link. Before you go splicing into the wiring, check continuity of the existing (on the car) fusible links to ensure you are chasing/fixing the right wires.

 

Yes i did notice the ga size difference and wanted confirmation and glad that i asked.
Oh for sure check continuity before splicing into the harness.
I wish they made better replacements for them since in the other post said the barrels are sealed.

 

The best way to install the replacement fusible links is to solder the new on in place of the one that was burnt. If you use crimp connectors or something similar to attach the fusible links it might cause the circuit to fail. You don't want to add any resistance in this circuit or the fusible link might be compromised. After soldering in the new Fusible link be sure to cover it with a good heat shrink to keep it from corroding.

On my 1968 C3 (VIN# 2595) I have two more fusible links down near the starter motor as well. I had a Electronic Cooling Fan Controller that self destructed and let the "smoke out". When it blew, one of the fusible links was burnt and at that point the dashboard and the fuse block were not powered either. My C3 was essentially "dead" electrically. After repairing the lower fusible link the car came back to normal and had full battery voltage at the fuse block.

I have a spare set for my 1968 in my garage and they all came from Amazon. They are still out there, you might have to do a bit of looking.

Never use anything but another Fusible link in place of the original. Not if you "Like" your Corvette at least...

If you test the fusible links by pushing a pin into the wire be sure to seal the holes when you are done. Otherwise water can get into the wire and cause corrosion inside the wire's jacket which will make other issues.

 

That is good information, I will check the ones going to the horn relay and the voltage regulator first. Then check by the starter. Do you have a pic of what they look like so i know i am getting the right ones.

 

The construction of the fusible links is that the wire size is smaller than the wire to which it is connected. Hence, it will fry before the wire it services. It has non-flammable insulation, so that an insulation fire will not start when the link wire fries. There will be a non-flammable termination "block" at each end to prevent heat from communicating to any attached 'normal' wire.
There is nothing 'special' about the wire in a fusible link, other than what is listed above.
Why did GM (and other mfgrs.) use fusible links? Well, they were only placed in wires connected to devices that COULD have internal failure that might generate a dead short. Starter/solenoid, horn relay, wiper motor, alternator and the like. These locations did not warrant fuses because fuses are more expensive and because the devices being protected are "high reliability" items that RARELY create a dead short. In fact, MOST instances of a fried fusible link in these vehicles are caused by mechanics or owners working on the electrical system without disconnecting the battery or by connecting other devices to the electrical system while the vehicle is in operation. (sound familiar?)
When the fusible link fails, the "expense" is the trouble to find the fault and then the cost of a fusible link. What folks don't recognize is, that the failure of that inexpensive link PREVENTED THE DESTRUCTION OF OTHER MORE EXPENSIVE COMPONENTS OR THE VEHICLE CATCHING FIRE!! Fusible links are a very simple, very effective, and very beneficial component in these old cars. Replace them with proper substitutes.

 

I get it,,, When checking the timing like i was doing should have disconnected the battery after the car was running ;-)...
Actually i have DC variable power supply and was going to use that for the timing light, just wish my timing light had long cables to connect directly to the battery and i wouldn't have been in this mess now. Well being new to corvettes is a learning experience and gald there are so many folks on here that have the wisdom to help someone not make the same mistakes.

 

Disconnecting the battery while checking the timing serves no purpose. The wiring is still energized by the alternator.
The battery disconnecting refrence applies to anytime you are working on the wiring to prevent an accidental grounding event that might blow a fuse or fry a link.