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Not sure what this hot wire goes to...

463 Views 16 Replies 8 Participants Last post by  jsm1847
FINALLY putting my wiring back together after 5 years or so of sitting. I have a larger hot wire running to the front of my engine bay from the solenoid. I don't know what the heck its to. Any ideas? I have a 350 with AC compressor, Electric fan, 650 Edelbrock. I dont think its for the fan because the fan is on the other side. What am I missing?
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Only large loads up front are the headlights and fan. Maybe the wire goes to a relay to feed one or the other.
You have been here 14 years and I still don't know what vehicle you are working on. Obviously, neither do you, or you'd tell us and maybe throw a picture or something at us. Any answer is purely speculation past post #1 :rolleyes:
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No pics, no description of what "large" means. So i'm going to wing a wild guess to you here that it might be the output of your alternator. Some wiring setups run the alternator output down to the solenoid to pickup the heavy (6+ awg) wire that runs from the solenoid to the battery.
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Either the alternator charge wire or the power wire to the electric fan relay. Probably the alternator.
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I would say this could be the hot wire to a junction terminal somewhere for the main battery feed to the system. On older cars with voltage regulators the wire would go on a terminal. Some older cars (50-60's) used the horn relay for a junction. Another wire on the same terminal went to the fuse panel and ignition switch. If this is the source of power to the system the wire should have a fusible link or fuse or circuit breaker to protect the wires.
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Thanks for the replies. I’ve been at work, so just able to get back to post. Here are the requested photos.
350 motor with coil and electronic ignition.

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The thicker wire is not the alternator, nor the fan. Those two wires are on the drivers side of the cab.
Picture one shows I’d guess a n 8 or 10 gauge wire to a 30-40 amp circuit breaker. That can support a pretty good load. Given there doesn’t seem to be any output wire near by it could be something that was removed from the truck in the distant past.

Picture two shows an ignition style resistor most often used to reduce 12 volts down to 6-9 into the coil when point ignition is used. That thought can extend into a few aftermarket and even factory electronic ignitions Chrysler did this on some models back in the 60’s and 70’s Ford and GM not so much.

Bogie
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Picture one shows I’d guess a n 8 or 10 gauge wire to a 30-40 amp circuit breaker. That can support a pretty good load. Given there doesn’t seem to be any output wire near by it could be something that was removed from the truck in the distant past.

Picture two shows an ignition style resistor most often used to reduce 12 volts down to 6-9 into the coil when point ignition is used. That thought can extend into a few aftermarket and even factory electronic ignitions Chrysler did this on some models back in the 60’s and 70’s Ford and GM not so much.

Bogie
I was thinking the same thing, that it was something removed in the past. Could it be an ahooga horn? I havent reinstalled that and I don’t see any wiring for it. But that seems kind of excessive for a horn…
I would have no idea, if there is no need for it I’d remove it.

I’d be more concerned with the ignition resistor and whether it’s really needed or not which takes you into identifying what’s inside the distributor by maker.

Bogie
I would have no idea, if there is no need for it I’d remove it.

I’d be more concerned with the ignition resistor and whether it’s really needed or not which takes you into identifying what’s inside the distributor by maker.

Bogie
Checked the specs for Mallory and it does call for the resistor. But thanks for the heads up!!
That’s something you have to check! The Malory was originally designed to replace points so they designed around a module that used 6 to 9 volts so it would be a drop in replacement.

As electronic ignition became standard the OEMs followed by most of the after market went to 12 volts as for the OEMs it simplified wiring in that stand alone resistors their mountings and electrical connections or more expensive resistive wire from ignition switch to distributor coil could be eliminated. Keep in mind that three cents per vehicle is 30,000 dollars per million vehicles and they make millions of vehicles. Most of the aftermarket started selling high performance modules for OEM distributors then graduated into the whole distributor so except for some early points conversions most of the aftermarket was aimed at the OEM 12 volt wiring with no changes for the installer.

Bogie
"Performance resistors". haha. You could literally take some of the older carbon resistors and shave them down to reduce the overall resistance and to deliver a higher voltage.

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Well start it up. If everything is working trace that wire back and cut/unhook it. If you cut it make sure to heatshrink it to avoid issues. I don't mess with that 70's resistor tech. Run a new wire etc if need be.
Well start it up. If everything is working trace that wire back and cut/unhook it. If you cut it make sure to heatshrink it to avoid issues. I don't mess with that 70's resistor tech. Run a new wire etc if need be.
Started today 👍🏼
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