Short on the main red wire

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   63 Rambler Classic, 10 series. 
Of course I knew better, but I did it anyway. I was cleaning up grounds and connectors under the hood with Deoxit, with the battery disconnected. Tightened everything back up and was just getting ready to turn over the engine when I noticed the horn relay. 
Figured “why not? while I was in there, and started wigging the connector to pop it off. What happened instead was that the entire relay separated and shorted to the frame. 

After I put the fire out (seriously), I started assessing the damage. The red wire insulation outside of the loom blew clean off. I figured I could go back to good wire then cap it off and run without a horn for a while until pulling out the wiring diagram. I had no idea it was connected directly to the battery. 

People who know more about electricity than me…after a short in the main battery line like that, is any of that wire still trustworthy or did I probably damage insulation along the way and a re-wire is in my future?

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tungsten Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Mar/09/2017 Location: Chicago, IL Status: Offline Points: 33	Post Options Post Reply Quote tungsten Report Post Thanks(0) Quote Reply Topic: Short on the main red wire Posted: Mar/08/2022 at 12:15pm
	63 Rambler Classic, 10 series. Of course I knew better, but I did it anyway. I was cleaning up grounds and connectors under the hood with Deoxit, with the battery disconnected. Tightened everything back up and was just getting ready to turn over the engine when I noticed the horn relay. Figured “why not? while I was in there, and started wigging the connector to pop it off. What happened instead was that the entire relay separated and shorted to the frame. After I put the fire out (seriously), I started assessing the damage. The red wire insulation outside of the loom blew clean off. I figured I could go back to good wire then cap it off and run without a horn for a while until pulling out the wiring diagram. I had no idea it was connected directly to the battery. People who know more about electricity than me…after a short in the main battery line like that, is any of that wire still trustworthy or did I probably damage insulation along the way and a re-wire is in my future?

bigbad69 Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jul/02/2007 Location: Ottawa, Ont. Status: Offline Points: 6666	Post Options Post Reply Quote bigbad69 Report Post Thanks(0) Quote Reply Posted: Mar/08/2022 at 3:03pm
	It sounds like you seriously overheated that wire, so you will probably have to trace it through the cable bundle and visually inspect the insulator. It could be damaged right back to the source. Depending upon how tight the bundle is wrapped, it may have melted the jackets of adjacent conductors. The only way to know the extent of the carnage is to inspect the whole bundle. Be sure to disconnect the battery before doing this. The secondary of the horn relay is tied to full time battery voltage, but I thought it was fused.
	69 Javelin SST BBO 390 T10

tungsten Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Mar/09/2017 Location: Chicago, IL Status: Offline Points: 33	Post Options Post Reply Quote tungsten Report Post Thanks(0) Quote Reply Posted: Mar/08/2022 at 3:46pm
	Looks like there’s unfused power going to both the horn and headlight switch. It’s crazy.

george w Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jan/27/2013 Location: New Jersey Status: Offline Points: 2899	Post Options Post Reply Quote george w Report Post Thanks(0) Quote Reply Posted: Mar/08/2022 at 4:31pm
	There may be a section of fusible link wire going to the hot side of the relay. Typically it could be pink or a different color than the main wire and be spliced somewhere in line with it. Usually fuseable link wire has a softer, more flexible insulation which makes it easier to identify from the usual copper wiring. As for the headlight switch, it should have an internal circuit breaker to protect the headlight circuit wiring leaving the switch. You may want to find a factory TSM wiring diagram to see if, it too, may have a fuseable link in line. Today’s car circuits are fused every which way from Sunday which most of us are used to seeing. It’s hard to believe that the earlier cars had so few circuits and so few fuses.
	Long time AMC fan. Ambassador 343, AMX 390, Hornet 360, Spirit 304 and Javelin 390. All but javelin bought new.

Mopar_guy Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jun/07/2009 Location: Ohio Status: Offline Points: 4825	Post Options Post Reply Quote Mopar_guy Report Post Thanks(0) Quote Reply Posted: Mar/08/2022 at 6:52pm
	I'm not surprised because a lot of the older cars didn't have any fuseable links. My neighbors 66 Corvette didn't have one on the main lead into the ignition switch. I would replace that burnt wire back to where it starts. Inspect the other wires in the harness for any damage. That should be all you need. I would add some sort of fuseable link or a maxi fuse in that circuit close to the battery.
	"Hemilina" My 1973, 5.7 Hemi swapped Javelin

Trader Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6875	Post Options Post Reply Quote Trader Report Post Thanks(0) Quote Reply Posted: Mar/08/2022 at 8:12pm
	Car audio systems have many 12VDC breakers available that are more then enough for a classic car. Some use them in places hidden so the car is harder to steel. You need approximately 150% above the total of all the amperages of your fused added up. An example that would likely suit a 63 Classic: https://www.walmart.com/ip/80-AMP-12V-DC-CIRCUIT-BREAKER-REPLACE-FUSE-80A-12VDC-CAR-AUDIO/676278773 The main wire to the fuse panel should be replaced and go directly to the breaker and then the fuse panel. The starting/generator circuit cannot go through the breaker, ignition should though.

tomj Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/27/2010 Location: earth Status: Offline Points: 7539	Post Options Post Reply Quote tomj Report Post Thanks(0) Quote Reply Posted: Mar/08/2022 at 11:21pm
	Not many fuses on the older cars. I'm used to it, but my 60 American surprised even me. One breaker for most "everything", 15 amps, lights other than headlamp, accessories, instrument panel, etc, one on the headlamp switch, that's it. Everything else to battery. Primitive. Power budget for the whole car, all of it, 15 amps. "Don't do that" is probably factory procedure.
	1960 Rambler Super two-door wagon, OHV auto 1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com