Electrical: My Shorts !!

[SuperHawk]

I do believe I have an electrical short in my "64 Daytona convertible, and I have spent about 25 hours now unsuccessfully trying to find it, so it's time to seek forum advice. A little background on the car and situation should come first.

Battery discharges itself in about 3 days of non driving. Battery is 1 1/2 years old, and I took it back to O'Reilly's where it was purchased for a load test. They said it was perfect. Then I took it to an auto electric shop that I really trust, and they also said it was perfect. The car is generously equipped with air, pusher fan in front of the condenser with both auto and manual switching, 200R4 overdrive automatic trans,and electric fuel pump. Oh, and I also installed driving lights just before the 2500 mile round trip drive to Colorado Springs. All the above circuits are on relays. Other "add-ons" include an under dash switch to turn on the back-up lights, an Edelbrock AFB clone carb with electric choke, a mechanical stop light switch, and a higher capacity non-stock alternator. I'll admit all this leaves plenty of opportunity for something to go wrong, but my belief, after doing a lot of testing, is that none of the circuitry involved with the above mentioned accessories is the culprit.

My method for finding a short initially involves keeping the positive battery cable connected, whilst disconnecting the negative. I then clamp one end of a test light to the negative battery cable end and touch the pointy end of the tester to the negative battery terminal. If the test light illuminates, that tells me there's a short somewhere.

I have disconnected the alternator. I have disconnected the starter wire from the starter solenoid. I have disconnected wires from the battery cable side of the solenoid, and the only wire that indicates a short is the one that has the 18 gage black horn relay wire mated to the 12 gage red wire that goes from the starter solenoid to the ammeter. When I take off that particular wire combo, my test light no longer lights up. The trouble is, the red wire that goes to the ammeter seems to power a lot of things.

So, I guess my 2 questions for the day are:

1) Is the procedure I am using to find a short correct; and

2) Is there a particular circuit that is normally more prone to shorts than others ??

As always, thank you for whatever advice you can offer.

Larry

[BobWaitz]

I'm not a pro at this but I have a couple ideas you could try. First, I'd use a multi-meter instead of a test light to find out how much current is being drawn with everything if only to make sure it is enough to power the test light when you do find it.

Next I would run your same test but take my fuses out one at a time to see which circuit is causing the problem.

Finally I would pull my special wire tracing tool out. Here's an example of a cheap one:

http://www.newark.com/jsp/search/productdetail.jsp?SKU=80R7549&CMP=KNC-GPLA&mckv=|pcrid|27090075021|plid|

I used to do a lot of phone switch work. The tool has two parts. The first is a tone generator. You hook that up to one end of the phone line. The other part is an inductive probe -- like the part of a timing light you clamp around the plug wire. The tone generator sends a signal down the line that the probe can pick up anywhere along the wire. It works great for chasing down parted or shorted wires on cars. I've lent it to one Stude guy who is a bus mechanic to trace wires from the front of a bus to the back. So anyway, a shorted wire is going to send that signal not just to its end terminal, but to the whole frame. So you'd clamp the tone generator on to the end of each wire until you are finding tone coming off the frame and that is the culprit.

Anyone who's ever worked in Telcom has one of these laying around. Just don't ever use it on a powered circuit -- especially an AC one.

And I didn't even make a joke about your hot, hot shorts!

[41 Frank]

If you are not able to find a device to find shorts you can resort to disconnecting one circuit at a time. First things you might check is the glove box light, if equipped. On my own Daytona convert sometimes the glove box light stays on.

[Bud]

Your problem doesn't sound like a short to me. I believe something is drawing down the battery like a glove box light, trunk light etc. not turning off. You need to put an ammeter in series with the positive lead to the battery to check for current draw which on an old Studebaker should be essentially zero with everything turned off. If you see a current draw, start pulling fuses or disconnecting individual circuits until you find the offending part. I've also seen leaky diodes in the alternator which will cause a current draw that is tough to find as the alternator will still charge but not at its rated output. Even a newer radio can draw down a battery as they have to be powered to maintain the memory in the radio. The 12 gauge red wire on the solenoid is the main feed for the electrical system in the car which should be connected to one side of the ammeter and everything except the starter and the horn runs through that circuit. There should be a black wire on the same terminal as red lead on the solenoid that goes to the horn relay. Bud

[Tom Bredehoft]

In addition to the lights you can't see, check the clock. If it's running, it takes about an amp jolt once every minute and half, if it's not running, the points could be welded and it could be a continuous drain. Of course, if you dont' have a clock, that isn't the problem.

[63 R2 Hawk]

You say all your added circuits are on relays, are they solid state relays or coil/contact type? I have seen the SS relays cause current leakage but still work. Maybe something to check. I don't see any problem with using the light bulb test lamp, I have a 1156 bulb with clip leads and a fuse soldered in line and enough wire so I can place it where I can see it as I disconnect things. I have used it to troubleshhoot current drains in several of my vehicles, best method I've found....

[Jet Green Daytona]

Larry, I just can't help myself, I hope you don't get offended. Anyhow, I am willing to help you out and give that car a good home in NJ, that way you won't have to worry about finding the short, I'll take it as is.


Todd
Jet Green Daytona

[RadioRoy]

Have you put in a modern radio? I put in a radio from Costco some years back and the memory keep alive circuit for the station preselect buttons would drain the battery in a couple of days.

[Jet Green Daytona]

In all seriousness Larry, I would also check any clock or radio that's in the car, and another thought is, could your starter being going bad? It could be drawing higher amps and draining the battery faster than it should? Or at least making it seem like the battery is dead, but it just doesn't have enough power to turn the starter motor. I had that happen in a car years ago, if the planets any everything else was aligned, the car would start right up, if they weren't the car acted like it had a dead battery and wouldn't turn over.

Todd

[SuperHawk]

Thank you one and all who responded to this inquiry.

I think I found the culprit: the clock!

Wierd thing, though, early on in my investigation I do remember disconnecting the fuse from the clock, and still my test light lit up, indicating to me there was a short. Some time later, I realized I was keeping the driver's door open, thus the courtesy light circuit was active. After realizing this, I disabled the courtesy light circuit, and started all over, re-testing the circuits I had done before. That's when I was able to isolate the clock as the problem.

I think things are okay now, but I don't know what time it is .....

Thanks again,

Larry

[RadioRoy]

It's Howdy Doody time!

[altair]

Thank you one and all who responded to this inquiry.

I think I found the culprit: the clock!

Wierd thing, though, early on in my investigation I do remember disconnecting the fuse from the clock, and still my test light lit up, indicating to me there was a short. Some time later, I realized I was keeping the driver's door open, thus the courtesy light circuit was active. After realizing this, I disabled the courtesy light circuit, and started all over, re-testing the circuits I had done before. That's when I was able to isolate the clock as the problem.

I think things are okay now, but I don't know what time it is .....

Thanks again,

Larry

I was doing the exact same test and I had the door open with the courtesy light on and the engine compartment light on in the daylight I didn't notice it. After I had completed the testing I still couldn't get the light to go out and put every thing away and did a night time walk around and found the glove box light was on plus an interior map light. These little deamons can be frustating

[jimmijim8]

Some one needs to tell of shorted circuits, open circuit difference, plus explain why an Ammeter is connected in series with a load and why voltage is measured from the positive side of a supplied load to auto/battery ground. I'm not good at splaining this. Would help a lot of folks when trouble shootin thus eliminating wrong terminology/confusion. A test light inserted in a series circuit will light but if the filament is burnt out the circuit will no longer be complete thus it is dead. Same as pulling a fuse. Please someone chime in. cheers jimmijim

[StudeRich]

Open: no continuity, or connection

Closed: does have current flow and continunity

Short: crossing the Negative circuit with the Positive creating heat and smoke and eventually Fire!

I do see people saying they have a short, when they really mean they have current flow, draining the Battery.

You lost me on this one:

Quote: "plus explain why an Ammeter is connected in series with a load and why voltage is measured from the positive side of a supplied load to auto/battery ground."

Some electrical terminology is very simple, and also understanding how it works and what will happen in a given situation, but when it comes to WHY, I am NOT your man.

One of the few people I know who knows that stuff is Gord, where are you buddy? It does not matter, Electrical, Mechanical, Chemical, Scientific, Gord has it DOWN!

[Swifster]

It's because the OP lives in... 'SPARKS'...