1958 Panel Truck - wiring help please!

[drcmusic7]

Hi Gang,

I'm new to the forum. I've restored a dozen or so other vintage cars/trucks but this is my first Chevy.

Here's my awesome new truck:


It's a 1958 panel truck that sits on a 96' Impala frame. It has a 350 engine with a auto transmission. Runs and drives great. It's awesome with the power brakes, steering, etc.

However, there is something draining the battery within 24 hours. The ONLY things hooked up are the ignition, brake lights and water temperature gauge. Brand new battery and wiring harness too. Alternator is charing at 13.5v when the truck is running. When I test for a drain with my multimeter I'm getting a very minimal 1mA drain. Not nearly enough to drain the battery that quickly. I took it to the parts store and they confirmed my reading with their computer.

I changed the ignition switch thinking perhaps something was broken within it and causing the battery to drain but that didn't work either.

Here are some pictures of the engine and harness:

Wires from the HEI distributor


The brake switch


The new fuse box. Please note all the wires are just rolled up on top of the steering column.



What am I missing that is causing this huge drain? I'm guessing there is a short somewhere but can't seem to find it.

Any advice would be greatly appreciated!

Thanks for your help,
Danny

[mr48chev]

That alternator should be charging around 14.2 volts to fully charge the battery when the truck is running down the road.

I wouldn't think that the top of the battery would be dirty on that truck as clean as the truck is but take a volt meter and put one wire on the matching battery post and touch the other at various spots across the top of the battery to see if there is a drain across the top of the battery.
We fought a similar condition in a student's truck when I was teaching auto mechanics and finally figured out that the drain (which at 1 spot was 9 volts) was across the dirt and moisture on the top of the battery. Pulled the battery out, scrubbed it up good and put it back in and no more problems. That truck's battery would drain down in about 3 hours to where the truck wouldn't start.

Since there is no sound system hooked up we can eliminate someone else playing the sound system while you are gone draining the battery. I had another student who's slick Impala lowrider had a dead battery every morning when he would leave for school. We checked it over several times and couldn't find anything wrong. Later his mom mentioned that his little brother and the brother's friends would play his stereo while he was at work in the evening. Somehow the brother lived to tell about it but the car was off limits after that. He left the car at home because he didn't want to park it in the lot at work and have it banged up.

[mr48chev]

After thinking on that a bit I'd have the alternator checked out to make sure that it doesn't have a blown diode. That would let it still charge some but might allow the drain you are seeing.

[drcmusic7]

Thanks, mr48chev! I appreciate your help.

The battery is brand new and tests fine. I'll check out the diode's. That's a great idea!

I traced every wire hooked up. Please excuse my bad handwriting and drawing but hopefully this diagram will show how things are currently hooked up.

Does it look correct?


Thanks,
Danny

[Coupeguy2001]

you are missing something.

Ignition switches are good for about 20 amps.
If you add up everything, I will bet that you come up with way more than 20 amps.
You have to have fusible links or equivalent somewhere in that thing.

On my 57, I have all the accessories running off of relays.
Relays take a heavy lead on the contact side, and the coil takes less than half of an amp. all the coils run off the key.

For instance, I have a 0 gauge wire running to my amplifier for my radio, but it runs off of a relay. the relay coil runs off the key.
The amp came with a 30 amp fuse. but the 30 amps don't run through the ignition switch.

My overdrive has a relay to turn it on. but that relay is run off of another relay that works off the ignition switch so the key can cancel it.

So, what do you have besides the alternator that runs off the battery direct?

The alternator diode is usually the problem because sometimes people get confused about how to hook up jumper cables and pop the diode trying to get a car with a dead battery started.
What I would do is find a 30 amp ammeter and hook up some leads to it so that you can put it on a battery cable and then hook the other end onto the battery. You should be able to see how many amps is draining the battery.
Then look at all your fuses, and start pulling them one at a time.
You will be able to see on the amp meter when the short or draw goes away.
I would loosen the red lead on the alternator before hooking up the ammeter when you have the battery disconnected to hook in the ammeter. That way, you don't have any tools on that lead, just your fingers. No chance of shorting it out that way.
If you can't determine what the draw is, put the key in the ignition switch, and wiggle it. if the ammeter needle wiggles too, you have a internal problem with the switch.

Probably not, since it's new, but hey, check everything.
Go to the back of the truck, and check your brake lights aren't staying on.
check the inside lights at night.
why do you have a 25 amp fuse for the horn? maybe the horn relay is stuck on?
The pink wire on your HEI is power
There are many ways to find your drain....

[Softpatch]

need more pictures .?
how are the wires connected to the wiring loom for the steering loom (IE) horn, turn,
backside of light switch, battery, horn relay,Carb choke, lockup converter.?
On your drawing what is (REA cutoff).?

[drcmusic7]

Coupeguy2001, thanks for your help! There is only one relay current hooked up. It's on the right side of the fuse box for the horn. I'm not sure why there is a 25amp fuse in there. I've only had the truck a week and that's the way it came. The horn does not work though. There are three wires running to the relay.

Here's a picture.



The steering column is from the 96' impala. It appears to be that the wires are almost all cut from the column as it has a separate ignition switch in the dash from the one on the column. However, I do have to put the column key in to unfreeze the steering wheel.

Nothing works from the steering column - horn, turn signals, etc, all not wired up.

Here's a picture of all the cut wires.


The wires from my ignition switch.


I checked with my multimeter for a parasitic draw but didn't find anything significant enough to drain the battery that quickly. I got a 1mA reading. I drove it to the parts house and their computer echoed that.

Would a bad diode not be apparent on that kind of test?

Softpath, Thanks for your help too! Hopefully the above pictures help. The auto choke isn't hooked up right now. Really not a ton of stuff hooked up which is why it's so confusing. It's almost a blank slate for me and I can't figure out what I'm missing from the previous owners wiring.

The "REA cutoff" is my bad handwriting it's RED cutoff. There is a wire from the BAT terminal on the ignition switch that leads no where and has electrical tape on the end.

Thanks again your help guys, I appreciate it.

Anything else I should look into?

Thanks,
Danny

[OrrieG]

Pull the fuses one at a time and check for draw at the negative battery terminal so you can isolate and rule out circuits. Looks like the ignition switch is being used as a power terminal block instead of the amp gauge. With what you have found, there is probably another hidden not used wire shorting to ground. Is the fuse box aftermarket or from another donor car?

[drcmusic7]

OrrieG, thanks for your help. I agree about the ignition switch. It's odd to me. Is there another way I could/should wire it?

I'm not sure about the fuse box. It looks brand new and so do all the wires. But i'm guessing it's aftermarket. I've been wondering if it's not grounded properly. Is there a way to test for that?

I thought about pulling all the fuses except for the brake lights until I finish what the previous owner started. Bad idea?

I just checked my alternator again and this time it read 14.17v.

Thanks,
Danny

[drcmusic7]

Quick question - With the engine turned off, I used my test light with the negative battery cable and negative battery terminal and the light came on. When I disconnect the red wire from the back of the alternator it goes off.

That indicates to me that you all are correct and a diode is draining the battery.

Is that line of thinking correct?

Thanks,
Danny

[JimDirt]

I am not sure , but i am questioning all the "Hot" leads going to/from the ignition switch , maybe causing a back feed or a power bleed maybe ?? , you should only have 1 as far as i know , and it should be coming FROM the fuse box to the ignition switch ,as the only hot TO the switch should be coming from the Fuse box , not direct from the battery , you should have a hot coming INTO the switch (from the fuse box) , then a Purple wire going out of the switch TO the Starter for Start Position , and a Ignition wire to power your various accessories/gauges , the power to the HEI should be also coming from the Fuse panel as should the Alt power lead (which can also come FROM a AMP gauge) , so everything is fused , , Brake light , power TO the column (if you decide to use that key instead of the dash switch) would also come from the fuse box , light switch power would come FROM the fuse box , but everything "should" run thru the panel , not direct to/from the key switch , ...... someone correct me if i am wrong here , i see that as a electrical fire waiting to happen , but power from the battery should only be going TO the fuse box , nothing else should be direct ...again , someone correct me if i am wrong here

[57chevyman]

is your battery in the stock location in the metal tray? i recall a mechanic telling me once to make sure the rubber mat is under the battery because without it power could drain out of the bottom of the battery

[drcmusic7]

Well I took the alternator to have the diodes check at advance auto and it passed. I took it too auto zone to double check and it failed.... not sure which one is correct so I bought a new one and just put it in. My test light is still lighting between the ground cable and negative terminal. I pulled every fuse and it stayed light too. Still showing only a 1ma on the multimeter. The ground cable is going to the firewall rather than the engine block. Could that be it? The engine is grounded to the frame.

Thanks, Jimdirt. I appreciate your help. That switch is sticking out to me too. I tired to draw out what you described but I'm struggling to visualize it. Can you please share a link to a wiring diagram like you're saying it should be?

57Chevyman, to the best of my knowledge it is. I did some reason into similar trucks and it saw pictures with the battery in the same spot. I can certainly try putting a piece of rubber or a mat under the battery.

Any other ideas?

Thanks!
Danny

[JimDirt]

Something on the lines of this (post #16)

http://67-72chevytrucks.com/vboard/s...d.php?t=393139

[drcmusic7]

Thanks, Jim. That is a huge help. Looking at that I noticed that the brown wire that is currently on my BAT terminal on my switch shouldn't be there. That would explain why my test light is always on when I check the negative terminal on the battery. I moved that wire to the ACC portion of the switch.


I now have red on BAT, pink on IGN, Purple on SOL, Brown (to the fuse box) and Brown (to the Alt) on ACC.

Sound OK? My test light is no longer lighting up on the battery ground and the alternator is charing at 14.26 now.

Thanks,
Danny

[JimDirt]

That's why i was mentioning back feeding , it seemed too much on the HOT lead , and other wires not where they should be , don't forget you need Fusible Link , or to go into the fuse box BEFORE the ignition switch , you don't want a "direct connection" to the key (or light switch) , should something short out you would have no way to stop it from melting everything , you need a buffer to stop the current flow , be it , inline fuse , fusible link , or a main fuse in the fuse box