Correct wiring on '70

[w00dst0ck]

Trying to work out all the wiring issues with this truck we just picked up.

I rewired the battery and fusibile link and now the truck is staying on with the ignition off and key removed.

-Fusbile link to post on passenger firewall
-Red power wire from post to the firewall (ignition hot)
-Red power wire on left side connected directly to battery crossing over to alternator

[w00dst0ck]

The other end of this connection was wired to that hot junction on the passenger side fender. I couldn't find this end until this morning.

On my buddies '72 his is a grounded to the core support with a fuse.

Looks like the rest of my wiring is correct, I just need to know where this fused connection goes. Doesn't really show on any of the colored diagrams I have seen. Also, what size fuse?

[71meangreenc10]

That wire is for the Ammeter. There should be one on each side. I will have to look at the schematic to show you were they are located.

Smitty

[w00dst0ck]

Long story short we picked the truck up everything ran fine. Original 307 with 40k miles

I was driving it to the shop when it just died. As soon as I rewired that junction block on the fender it had power again. But now it won't turn off with the ignition.

And I noticed after it died that the other end of that fused junction was missing. So I'm thinking maybe it got pulled off somehow.

I'm just wondering if this is my issue, or the ignition switch is taking a dump.

The ammeter in the truck is working though, even with this unplugged. However, ever since I rewired to the picture above, it seems something has a hot constant because the battery is completely dead now.

[71meangreenc10]

If the fuses are missing, the Ammeter shouldnt work. The needle may be moved, but if it was working correctly you would see it move back and forth with the truck running. I would not think that this would cause your issue. Check the ignition switch if it ran fine before. Has the truck been changed over to a internal regulator, HEI, etc....

Smitty

[w00dst0ck]

I honestly haven't been able to get it to the shop to look at it yet, but it looks original. The external regulator is still mounted to the front support.

[71meangreenc10]

Check the switch and check the wiring going into the switch.

Smitty

[w00dst0ck]

I was just going to throw a new BWD switch in it. It's only $22. About to take it to the shop and check it with the meter though.

Does the passenger side ammeter get grounded after the fuse?

[w00dst0ck]

Unplugged the ignition switch and the battery seemed to stop draining so I grabbed a new one that I'm going to throw in tomorrow morning.

Also fixed the tail lights, someone unplugged the connector from the fuse panel. Still losing 1 brake light occasionally, pretty sure there's a short somewhere along the frame rail.

[w00dst0ck]

Put a new switch in it and I'm still having the same issue. Won't turn off with the key.

Unplugged the alternator with key out and it still didn't kill it, so I'm not sure if backfeed is the problem.

Any ideas?

[w00dst0ck]

whoops double post.

[w00dst0ck]

Should anything be plugged into the unfused ignition slot? I have an extra connector that I haven't figured out where it goes yet.

[w00dst0ck]

Found the culprit. Someone used a wire nut on the dizzy ignition feed, and it's getting 12v constant.

Anyone know where this pink wire goes? From the diagrams it looks like 12 pink 38, but I can't tell where it goes once inside the cab.

[71meangreenc10]

That was the next area i was going to run you into. Looks like a connector for the dome light. I can check mine.

Smitty

[w00dst0ck]

I traced that pink wire all the way back to the ignition and its constant hot all the way. So ideally I would like to know what wire it was originally supposed to go to. Otherwise I will just have to run a new switched 12v from the switch

[FirstOwner69]

Originally Posted by w00dst0ck

Trying to work out all the wiring issues with this truck we just picked up.

I rewired the battery and fusibile link and now the truck is staying on with the ignition off and key removed.

-Fusbile link to post on passenger firewall
-Red power wire from post to the firewall (ignition hot)
-Red power wire on left side connected directly to battery crossing over to alternator

EDIT: Sounds like you may have solved the riddle while I was typing this...

I've been hesitant to respond to this thread since I am no expert. However, when I compare the original wiring on my 69 to your first picture I see significant differences. The first question that pops into my mind is "why so many wires hooked to the positive battery post"? My 69 only has the battery cable and the fusible link running from the positive post. The battery cable goes to the starter and the fusible link goes to the junction block on the fender. There are only 3 other wires attached to the junction block: (1) A 12 gauge red that runs through the conduit on top of the core support to driver's side and eventually to the alternator. (2) A 16 or 18 gauge black with white stripe wire (alternator shunt if I remember correctly) that also runs through the core support conduit with a short 4 amp fuse (fuse holder you show in post 2) at each end (3) A 12 gauge red (which you wouldn't have unless you have the camper harness) which is the hot wire for my factory installed camper wiring harness that gets clipped to a lip on the core support.

The wire you mention that confuses me most is the one you describe as "-Red power wire from post to the firewall (ignition hot)". Where does go when it gets to the firewall?

The first picture below shows my junction box from the back side. The second picture shows one of the fuse holders at each end of the alternator shunt wire and a factory soldered junction that is bundled in the tape wrapped harness behind the left headlight. If you look closely you can see where the black with white stripe alternator shunt wire terminates. IF I recall correctly red wires run from here to the alternator and voltage regulator.

[w00dst0ck]

PO wired the alternator to the battery post instead of the fusible link, the other wire is fused power for the updated headlight wiring. And the only other wire is the fusibile link to the post. So aside from the alternator wiring it's the same as yours.

[w00dst0ck]

According to all the wiring schematics I've looked at my dizzy is wired correctly all the way to the firewall, minus the junction going down to the starter solenoid? Just curious why this would be a constant power and not switched. I was thinking maybe it had a short or touching a hot wire, but traced it all the way to the ignition switch (I believe, I didn't open up the loom).

[w00dst0ck]

Looks like my issue is related. PO wired it wrong im assuming.

http://67-72chevytrucks.com/vboard/s...d.php?t=373383

So since I'm running an HEI, the ignition source should be an unfused slot on the fuse block?

[FirstOwner69]

Originally Posted by w00dst0ck

According to all the wiring schematics I've looked at my dizzy is wired correctly all the way to the firewall, minus the junction going down to the starter solenoid? Just curious why this would be a constant power and not switched. I was thinking maybe it had a short or touching a hot wire, but traced it all the way to the ignition switch (I believe, I didn't open up the loom).

Since your truck was converted to HEI here's a link that may help you sort out the wiring. There should be a 12 gauge wire from the distributor to an ignition unfused source to replace the original resistor wire to the distributor.

http://67-72chevytrucks.com/vboard/s...d.php?t=431086

[FirstOwner69]

The ignition unfused source can be through the firewall to the fuse block, probably directly to the switch or (as I did) a total replacement of the resistor wire from the under hood side of the fuse block to the distributor.

[w00dst0ck]

There is an unfused switched power wire already running in the engine bay and not connected to anything, however it's not 12gauge, but it's the same gauge as the switched power coming off the dizzy. The unused slot is right below the fuel gauge connection.

The unfused ignition slots in my fuse block are constant 12v as well so those slots won't work.

[FirstOwner69]

Originally Posted by w00dst0ck

There is an unfused switched power wire already running in the engine bay and not connected to anything, however it's not 12gauge, but it's the same gauge as the switched power coming off the dizzy. The unused slot is right below the fuel gauge connection.

The unfused ignition slots in my fuse block are constant 12v as well so those slots won't work.

Where does that unused switched power wire originate? Is it actually the original resistor wire from the under hood side of the fuse block?

I thought ignition unfused was supposed to be hot only when the ignition switch is on.

Did you answer the question about where the "-Red power wire from post to the firewall (ignition hot)" terminates?

[w00dst0ck]

Red wire from post is ignition constant. unused slot I'm using now is switched power that feeds brake lights,dome, and traffic. I'm assuming it originates at the switch.

On my fuse block, ignition unfused are constant hot, which appears to be going straight to the switch.